diff --git a/CLAUDE.md b/CLAUDE.md
index a66314ecc02e..f2022078578d 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -6,3 +6,4 @@
 6. When instructed to fix tests, do not remove or modify existing tests.
 7. Write documentation for your code.
 8. Run `cargo fmt --all` before commiting files.
+9. Place all import statements at the top of the file for consistency. Do not use inline `use` statements within functions or impl blocks.
diff --git a/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.js b/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.js
index bfdac51518e2..4b652f6e1e7b 100644
--- a/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.js
+++ b/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.js
@@ -1,7 +1,7 @@
-(void 0).setStatus({message:`${(void 0).message} ${(void 0).code?`
+let e;(void 0).setStatus({message:`${e.message} ${e.code?`
 Mon	go
 os
 e Error
  C
 od
-e: ${(void 0).code}`:"1\n23"}`});
+e: ${e.code}`:"1\n23"}`});
diff --git a/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.map b/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.map
index c57344de4dc3..846fe9fabae5 100644
--- a/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.map
+++ b/crates/swc/tests/fixture/sourcemap/issue-9567/output/index.map
@@ -1,10 +1,10 @@
 {
-  "mappings": "AAAaA,CAAAA,KAAAA,CAAG,EACTC,SAAS,CAAC,CACXC,QAAS,CAAC,EAAEC,AAFCA,CAAAA,KAAAA,CAAI,EAECD,OAAO,CAAC,CAAC,EACvBC,AAHSA,CAAAA,KAAAA,CAAI,EAGPC,IAAI,CACJ;AAAG;AAAS;AAC5B;AAAS;AACT;AAAI,GAAG,EAAED,AANUA,CAAAA,KAAAA,CAAI,EAMRC,IAAI,CAAC,CAAC,CACL,QACT,CAAC,AACN",
+  "mappings": "IAAmBA,EACjBC,SAAKC,SAAS,CAAC,CACXC,QAAS,CAAC,EAAEH,EAAMG,OAAO,CAAC,CAAC,EACvBH,EAAMI,IAAI,CACJ;AAAG;AAAS;AAC5B;AAAS;AACT;AAAI,GAAG,EAAEJ,EAAMI,IAAI,CAAC,CAAC,CACL,QACT,CAAC,AACN",
   "names": [
+    "error",
     "span",
     "setStatus",
     "message",
-    "error",
     "code"
   ],
   "sources": [
diff --git a/crates/swc/tests/tsc-references/typeFromPropertyAssignment36.2.minified.js b/crates/swc/tests/tsc-references/typeFromPropertyAssignment36.2.minified.js
index 39f3e283ce2e..ee6fe9b3e717 100644
--- a/crates/swc/tests/tsc-references/typeFromPropertyAssignment36.2.minified.js
+++ b/crates/swc/tests/tsc-references/typeFromPropertyAssignment36.2.minified.js
@@ -1,8 +1,8 @@
 //// [typeFromPropertyAssignment36.ts]
 function d() {}
-(function(b) {
+(function() {
     function d() {}
-    return d.e = 12, d.e, b && (d.q = !1), d.q, b ? d.q = !1 : d.q = !0, d.q, b ? d.r = 1 : d.r = 2, d.r, b && (d.s = 'hi'), d;
+    return d.e = 12, d.e, d.q = !1, d.q, d.q = !1, d.q, d.r = 1, d.r, d.s = 'hi', d;
 })(!0).s, d.e = 12, d.e, d.q, d.q = !0, d.q, d.r = 2, d.r;
 var g = function() {};
 g.expando, g.both = 0, g.both;
diff --git a/crates/swc/tests/vercel/full/firebase/dist/1/output/index.js b/crates/swc/tests/vercel/full/firebase/dist/1/output/index.js
index 60a74d7871d0..2423ce91314f 100644
--- a/crates/swc/tests/vercel/full/firebase/dist/1/output/index.js
+++ b/crates/swc/tests/vercel/full/firebase/dist/1/output/index.js
@@ -1,4 +1,5 @@
-var e, t = require("@firebase/util"), n = require("tslib"), r = require("@firebase/component"), i = require("@firebase/app"), a = require("@firebase/logger"), o = function(e) {
+let e;
+var t, n = require("@firebase/util"), r = require("tslib"), i = require("@firebase/component"), a = require("@firebase/app"), o = require("@firebase/logger"), p = function(e) {
     if (e && e.__esModule) return e;
     var t = Object.create(null);
     return e && Object.keys(e).forEach(function(n) {
@@ -12,10 +13,10 @@ var e, t = require("@firebase/util"), n = require("tslib"), r = require("@fireba
             });
         }
     }), t.default = e, Object.freeze(t);
-}(i), p = function() {
+}(a), s = function() {
     function e(e, t) {
         var n = this;
-        this._delegate = e, this.firebase = t, i._addComponent(e, new r.Component("app-compat", function() {
+        this._delegate = e, this.firebase = t, a._addComponent(e, new i.Component("app-compat", function() {
             return n;
         }, "PUBLIC")), this.container = e.container;
     }
@@ -45,20 +46,20 @@ var e, t = require("@firebase/util"), n = require("tslib"), r = require("@fireba
         return new Promise(function(t) {
             e._delegate.checkDestroyed(), t();
         }).then(function() {
-            return e.firebase.INTERNAL.removeApp(e.name), i.deleteApp(e._delegate);
+            return e.firebase.INTERNAL.removeApp(e.name), a.deleteApp(e._delegate);
         });
     }, e.prototype._getService = function(e, t) {
-        void 0 === t && (t = i._DEFAULT_ENTRY_NAME), this._delegate.checkDestroyed();
+        void 0 === t && (t = a._DEFAULT_ENTRY_NAME), this._delegate.checkDestroyed();
         var n, r = this._delegate.container.getProvider(e);
         return r.isInitialized() || (null == (n = r.getComponent()) ? void 0 : n.instantiationMode) !== "EXPLICIT" || r.initialize(), r.getImmediate({
             identifier: t
         });
     }, e.prototype._removeServiceInstance = function(e, t) {
-        void 0 === t && (t = i._DEFAULT_ENTRY_NAME), this._delegate.container.getProvider(e).clearInstance(t);
+        void 0 === t && (t = a._DEFAULT_ENTRY_NAME), this._delegate.container.getProvider(e).clearInstance(t);
     }, e.prototype._addComponent = function(e) {
-        i._addComponent(this._delegate, e);
+        a._addComponent(this._delegate, e);
     }, e.prototype._addOrOverwriteComponent = function(e) {
-        i._addOrOverwriteComponent(this._delegate, e);
+        a._addOrOverwriteComponent(this._delegate, e);
     }, e.prototype.toJSON = function() {
         return {
             name: this.name,
@@ -66,76 +67,76 @@ var e, t = require("@firebase/util"), n = require("tslib"), r = require("@fireba
             options: this.options
         };
     }, e;
-}(), s = ((e = {})["no-app"] = "No Firebase App '{$appName}' has been created - call Firebase App.initializeApp()", e["invalid-app-argument"] = "firebase.{$appName}() takes either no argument or a Firebase App instance.", e), c = new t.ErrorFactory("app-compat", "Firebase", s), u = function e() {
-    var r = function(e) {
-        var n = {}, r = {
+}(), c = ((t = {})["no-app"] = "No Firebase App '{$appName}' has been created - call Firebase App.initializeApp()", t["invalid-app-argument"] = "firebase.{$appName}() takes either no argument or a Firebase App instance.", t), u = new n.ErrorFactory("app-compat", "Firebase", c), l = function e() {
+    var t = function(e) {
+        var t = {}, r = {
             __esModule: !0,
             initializeApp: function(i, a) {
                 void 0 === a && (a = {});
-                var p = o.initializeApp(i, a);
-                if (t.contains(n, p.name)) return n[p.name];
-                var s = new e(p, r);
-                return n[p.name] = s, s;
+                var o = p.initializeApp(i, a);
+                if (n.contains(t, o.name)) return t[o.name];
+                var s = new e(o, r);
+                return t[o.name] = s, s;
             },
             app: i,
-            registerVersion: o.registerVersion,
-            setLogLevel: o.setLogLevel,
-            onLog: o.onLog,
+            registerVersion: p.registerVersion,
+            setLogLevel: p.setLogLevel,
+            onLog: p.onLog,
             apps: null,
-            SDK_VERSION: o.SDK_VERSION,
+            SDK_VERSION: p.SDK_VERSION,
             INTERNAL: {
-                registerComponent: function(n) {
-                    var a = n.name, p = a.replace("-compat", "");
-                    if (o._registerComponent(n) && "PUBLIC" === n.type) {
+                registerComponent: function(t) {
+                    var a = t.name, o = a.replace("-compat", "");
+                    if (p._registerComponent(t) && "PUBLIC" === t.type) {
                         var s = function(e) {
-                            if (void 0 === e && (e = i()), "function" != typeof e[p]) throw c.create("invalid-app-argument", {
+                            if (void 0 === e && (e = i()), "function" != typeof e[o]) throw u.create("invalid-app-argument", {
                                 appName: a
                             });
-                            return e[p]();
+                            return e[o]();
                         };
-                        void 0 !== n.serviceProps && t.deepExtend(s, n.serviceProps), r[p] = s, e.prototype[p] = function() {
-                            for(var e = [], t = 0; t < arguments.length; t++)e[t] = arguments[t];
-                            return this._getService.bind(this, a).apply(this, n.multipleInstances ? e : []);
+                        void 0 !== t.serviceProps && n.deepExtend(s, t.serviceProps), r[o] = s, e.prototype[o] = function() {
+                            for(var e = [], n = 0; n < arguments.length; n++)e[n] = arguments[n];
+                            return this._getService.bind(this, a).apply(this, t.multipleInstances ? e : []);
                         };
                     }
-                    return "PUBLIC" === n.type ? r[p] : null;
+                    return "PUBLIC" === t.type ? r[o] : null;
                 },
                 removeApp: function(e) {
-                    delete n[e];
+                    delete t[e];
                 },
                 useAsService: function(e, t) {
                     return "serverAuth" === t ? null : t;
                 },
-                modularAPIs: o
+                modularAPIs: p
             }
         };
         function i(e) {
-            if (e = e || o._DEFAULT_ENTRY_NAME, !t.contains(n, e)) throw c.create("no-app", {
+            if (e = e || p._DEFAULT_ENTRY_NAME, !n.contains(t, e)) throw u.create("no-app", {
                 appName: e
             });
-            return n[e];
+            return t[e];
         }
         return r.default = r, Object.defineProperty(r, "apps", {
             get: function() {
-                return Object.keys(n).map(function(e) {
-                    return n[e];
+                return Object.keys(t).map(function(e) {
+                    return t[e];
                 });
             }
         }), i.App = e, r;
-    }(p);
-    return r.INTERNAL = n.__assign(n.__assign({}, r.INTERNAL), {
+    }(s);
+    return t.INTERNAL = r.__assign(r.__assign({}, t.INTERNAL), {
         createFirebaseNamespace: e,
         extendNamespace: function(e) {
-            t.deepExtend(r, e);
+            n.deepExtend(t, e);
         },
-        createSubscribe: t.createSubscribe,
-        ErrorFactory: t.ErrorFactory,
-        deepExtend: t.deepExtend
-    }), r;
-}(), l = new a.Logger("@firebase/app-compat");
-if (t.isBrowser() && void 0 !== self.firebase) {
-    l.warn("\n    Warning: Firebase is already defined in the global scope. Please make sure\n    Firebase library is only loaded once.\n  ");
-    var d = self.firebase.SDK_VERSION;
-    d && d.indexOf("LITE") >= 0 && l.warn("\n    Warning: You are trying to load Firebase while using Firebase Performance standalone script.\n    You should load Firebase Performance with this instance of Firebase to avoid loading duplicate code.\n    ");
+        createSubscribe: n.createSubscribe,
+        ErrorFactory: n.ErrorFactory,
+        deepExtend: n.deepExtend
+    }), t;
+}(), d = new o.Logger("@firebase/app-compat");
+if (n.isBrowser() && void 0 !== self.firebase) {
+    d.warn("\n    Warning: Firebase is already defined in the global scope. Please make sure\n    Firebase library is only loaded once.\n  ");
+    var f = self.firebase.SDK_VERSION;
+    f && f.indexOf("LITE") >= 0 && d.warn("\n    Warning: You are trying to load Firebase while using Firebase Performance standalone script.\n    You should load Firebase Performance with this instance of Firebase to avoid loading duplicate code.\n    ");
 }
-i.registerVersion("@firebase/app-compat", "0.1.5", void 0), module.exports = u;
+a.registerVersion("@firebase/app-compat", "0.1.5", e), module.exports = l;
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
index 87bd81052933..24379707c395 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/mod.rs
@@ -46,6 +46,7 @@ mod iife;
 mod inline;
 mod loops;
 mod ops;
+mod params;
 mod props;
 mod rest_params;
 mod sequences;
@@ -91,6 +92,7 @@ pub(super) fn optimizer<'a>(
         ctx,
         mode,
         functions: Default::default(),
+        inlined_params: Default::default(),
     }
 }
 
@@ -240,6 +242,11 @@ struct Optimizer<'a> {
     mode: &'a dyn Mode,
 
     functions: Box<FxHashMap<Id, FnMetadata>>,
+
+    /// Tracks which parameter indices have been inlined for each function.
+    /// Maps function ID to a sorted vector of parameter indices that were
+    /// removed.
+    inlined_params: Box<FxHashMap<Id, Vec<usize>>>,
 }
 
 #[derive(Default)]
@@ -1683,6 +1690,9 @@ impl VisitMut for Optimizer<'_> {
 
         self.ignore_unused_args_of_iife(e);
         self.inline_args_of_iife(e);
+
+        // Remove arguments for parameters that have been inlined
+        self.remove_inlined_call_args(e);
     }
 
     #[cfg_attr(feature = "debug", tracing::instrument(level = "debug", skip_all))]
@@ -2094,6 +2104,9 @@ impl VisitMut for Optimizer<'_> {
 
         self.drop_unused_params(&mut f.function.params);
 
+        // Inline parameters that are consistently passed the same constant value
+        self.inline_function_parameters(&mut f.function, &f.ident.to_id());
+
         let ctx = self
             .ctx
             .clone()
@@ -2110,6 +2123,9 @@ impl VisitMut for Optimizer<'_> {
             self.functions
                 .entry(ident.to_id())
                 .or_insert_with(|| FnMetadata::from(&*e.function));
+
+            // Inline parameters for named function expressions
+            self.inline_function_parameters(&mut e.function, &ident.to_id());
         }
 
         if !self.options.keep_fnames {
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/params.rs b/crates/swc_ecma_minifier/src/compress/optimize/params.rs
new file mode 100644
index 000000000000..6da5edaa4fa0
--- /dev/null
+++ b/crates/swc_ecma_minifier/src/compress/optimize/params.rs
@@ -0,0 +1,592 @@
+use swc_common::DUMMY_SP;
+use swc_ecma_ast::*;
+
+use super::Optimizer;
+use crate::program_data::{ScopeData, VarUsageInfoFlags};
+
+/// Methods related to parameter inlining optimization.
+impl Optimizer<'_> {
+    /// Inline function parameters that are consistently passed the same
+    /// constant value.
+    ///
+    /// This optimization identifies function parameters where all call sites
+    /// pass the same constant value (including implicit undefined), and
+    /// transforms the function to use a variable declaration instead.
+    ///
+    /// Example:
+    /// ```js
+    /// function complex(foo, fn) {
+    ///     if (Math.random() > 0.5) throw new Error();
+    ///     return fn?.(foo);
+    /// }
+    /// complex("foo");
+    /// complex("bar");
+    /// complex("baz");
+    /// ```
+    /// =>
+    /// ```js
+    /// function complex(foo) {
+    ///     const fn = undefined; // const if not reassigned, let otherwise
+    ///     if (Math.random() > 0.5) throw new Error();
+    ///     return fn?.(foo);
+    /// }
+    /// complex("foo");
+    /// complex("bar");
+    /// complex("baz");
+    /// ```
+    pub(super) fn inline_function_parameters(&mut self, f: &mut Function, fn_id: &Id) {
+        // Skip if optimization is disabled
+        if self.options.inline == 0 && !self.options.reduce_vars {
+            return;
+        }
+
+        // Skip if function uses eval or with statement
+        if let Some(scope_data) = self.data.scopes.get(&f.ctxt) {
+            if scope_data.intersects(ScopeData::HAS_EVAL_CALL | ScopeData::HAS_WITH_STMT) {
+                return;
+            }
+        }
+
+        // Skip if function uses arguments object
+        if let Some(scope_data) = self.data.scopes.get(&f.ctxt) {
+            if scope_data.contains(ScopeData::USED_ARGUMENTS) {
+                return;
+            }
+        }
+
+        // Get usage info for the function
+        let usage = match self.data.vars.get(fn_id) {
+            Some(u) => u,
+            None => return,
+        };
+
+        // Skip if function is exported, reassigned, or inlining is prevented
+        if usage.flags.contains(VarUsageInfoFlags::EXPORTED)
+            || usage.flags.contains(VarUsageInfoFlags::INLINE_PREVENTED)
+            || usage.flags.contains(VarUsageInfoFlags::REASSIGNED)
+        {
+            return;
+        }
+
+        // Skip if function is used as a reference/argument (not just called)
+        // Check if the function is used in ways other than being called directly
+        // USED_AS_ARG indicates the function is passed to another function, which means
+        // we don't have visibility into all call sites
+        if usage.flags.contains(VarUsageInfoFlags::USED_AS_ARG) {
+            return;
+        }
+
+        // Get call site arguments
+        let call_sites = match &usage.call_site_args {
+            Some(sites) if !sites.is_empty() => sites,
+            _ => return,
+        };
+
+        // Check if all call sites are known (callee_count should match call_sites
+        // length)
+        if usage.callee_count as usize != call_sites.len() {
+            return;
+        }
+
+        // Analyze each parameter
+        let mut params_to_inline: Vec<(usize, Box<Expr>)> = Vec::new();
+
+        for (param_idx, param) in f.params.iter().enumerate() {
+            // Only handle simple identifier parameters
+            let param_id = match &param.pat {
+                Pat::Ident(ident) => ident.id.to_id(),
+                _ => continue, // Skip destructuring, rest params, etc.
+            };
+
+            // Check if this parameter is shadowed by a function declaration in the body
+            // Function declarations are hoisted and would conflict with the inlined
+            // `let` declaration
+            if self.is_param_shadowed_by_fn_decl(f, &param_id) {
+                continue;
+            }
+
+            // Check if this parameter has the same name as the function itself
+            // This would cause shadowing issues when we create a `let` declaration
+            if param_id == *fn_id {
+                continue;
+            }
+
+            // Collect argument values for this parameter across all call sites
+            // Use Option<Option<Box<Expr>>> to track:
+            // - None = no common value yet established
+            // - Some(None) = all call sites have implicit undefined
+            // - Some(Some(expr)) = all call sites have the same explicit expression
+            let mut common_value: Option<Option<Box<Expr>>> = None;
+            let mut inlinable = true;
+
+            for call_site in call_sites {
+                // Get argument at this position, or None if implicit undefined
+                let arg_value: Option<Box<Expr>> = if param_idx < call_site.len() {
+                    call_site[param_idx].clone()
+                } else {
+                    None // Implicit undefined
+                };
+
+                // Check if this is a safe, constant value to inline
+                if let Some(ref expr) = arg_value {
+                    if !self.is_safe_constant_for_param_inline(expr) {
+                        inlinable = false;
+                        break;
+                    }
+                }
+                // Implicit undefined (None) is always safe to inline
+
+                match &common_value {
+                    None => {
+                        // First call site, establish the common value
+                        common_value = Some(arg_value);
+                    }
+                    Some(existing) => {
+                        // Check if this call site has the same value
+                        if !self.arg_eq(existing, &arg_value) {
+                            inlinable = false;
+                            break;
+                        }
+                    }
+                }
+            }
+
+            // If all call sites pass the same constant value, mark for inlining
+            if inlinable {
+                if let Some(Some(value)) = &common_value {
+                    // Inline the constant value
+                    params_to_inline.push((param_idx, value.clone()));
+                } else if let Some(None) = common_value {
+                    // All call sites have implicit undefined
+                    let undefined_expr = Box::new(Expr::Ident(Ident::new(
+                        "undefined".into(),
+                        DUMMY_SP,
+                        self.ctx.expr_ctx.unresolved_ctxt,
+                    )));
+                    params_to_inline.push((param_idx, undefined_expr));
+                }
+            }
+        }
+
+        // Apply the parameter inlining transformation
+        // Only inline if we can inline a contiguous suffix of parameters to avoid
+        // creating parameter lists with "holes" that might confuse other optimizations
+        if !params_to_inline.is_empty() {
+            // Sort by parameter index to check for contiguity
+            let mut sorted_for_check = params_to_inline.clone();
+            sorted_for_check.sort_by_key(|(idx, _)| *idx);
+
+            // Check if the parameters form a contiguous suffix
+            let mut is_valid_suffix = true;
+            let total_params = f.params.len();
+            let first_inline_idx = sorted_for_check[0].0;
+
+            // Must start at some index and continue to the end
+            if first_inline_idx + sorted_for_check.len() != total_params {
+                is_valid_suffix = false;
+            } else {
+                // Check contiguity
+                for (i, (idx, _)) in sorted_for_check.iter().enumerate() {
+                    if *idx != first_inline_idx + i {
+                        is_valid_suffix = false;
+                        break;
+                    }
+                }
+            }
+
+            if is_valid_suffix {
+                self.apply_param_inlining(f, &params_to_inline, fn_id);
+            }
+        }
+    }
+
+    /// Apply parameter inlining transformation to a function.
+    fn apply_param_inlining(
+        &mut self,
+        f: &mut Function,
+        params_to_inline: &[(usize, Box<Expr>)],
+        fn_id: &Id,
+    ) {
+        // Sort in reverse order to remove from the end first
+        let mut sorted_params = params_to_inline.to_vec();
+        sorted_params.sort_by(|a, b| b.0.cmp(&a.0));
+
+        // Collect variable declarations to add at the beginning of function body
+        let mut var_decls = Vec::new();
+
+        // Track which parameter indices are being inlined (will be sorted)
+        let mut inlined_indices = Vec::new();
+
+        for (param_idx, value) in &sorted_params {
+            inlined_indices.push(*param_idx);
+
+            if let Some(param) = f.params.get(*param_idx) {
+                if let Pat::Ident(ident) = &param.pat {
+                    // Create variable declaration: let paramName = value;
+                    // Always use 'let' to preserve parameter semantics (reassignable)
+                    var_decls.push(Stmt::Decl(Decl::Var(Box::new(VarDecl {
+                        span: DUMMY_SP,
+                        ctxt: Default::default(),
+                        kind: VarDeclKind::Let,
+                        declare: false,
+                        decls: vec![VarDeclarator {
+                            span: DUMMY_SP,
+                            name: Pat::Ident(ident.clone()),
+                            init: Some(value.clone()),
+                            definite: false,
+                        }],
+                    }))));
+                }
+            }
+        }
+
+        // Remove parameters (in reverse order)
+        for (param_idx, _) in &sorted_params {
+            f.params.remove(*param_idx);
+        }
+
+        // Add variable declarations to function body
+        if let Some(body) = &mut f.body {
+            var_decls.reverse(); // Reverse to maintain original order
+            var_decls.append(&mut body.stmts);
+            body.stmts = var_decls;
+        }
+
+        // Store the inlined parameter indices for later use when visiting call
+        // sites. Reverse sort to get descending order for efficient removal.
+        inlined_indices.sort_by(|a, b| b.cmp(a));
+        self.inlined_params.insert(fn_id.clone(), inlined_indices);
+
+        self.changed = true;
+        report_change!(
+            "params: Inlined {} parameter(s) for function '{}{:?}'",
+            params_to_inline.len(),
+            fn_id.0,
+            fn_id.1
+        );
+    }
+
+    /// Check if an expression is a safe constant value for parameter inlining.
+    fn is_safe_constant_for_param_inline(&self, expr: &Expr) -> bool {
+        match expr {
+            // Literal values are always safe
+            Expr::Lit(Lit::Null(_))
+            | Expr::Lit(Lit::Bool(_))
+            | Expr::Lit(Lit::Num(_))
+            | Expr::Lit(Lit::Str(_))
+            | Expr::Lit(Lit::BigInt(_)) => true,
+
+            // Only allow unresolved "undefined" identifier
+            // We DO NOT inline variable references because:
+            // 1. It doesn't save code (just moves a reference)
+            // 2. It can interfere with other optimizations
+            // 3. The goal is to inline actual constants, not variable names
+            Expr::Ident(id) => {
+                let is_unresolved = id.ctxt == self.ctx.expr_ctx.unresolved_ctxt;
+                // Only allow unresolved "undefined"
+                is_unresolved && id.sym == "undefined"
+            }
+
+            // Negated or numeric-negated literals
+            Expr::Unary(UnaryExpr {
+                op: UnaryOp::Bang | UnaryOp::Minus,
+                arg,
+                ..
+            }) => self.is_safe_constant_for_param_inline(arg),
+
+            // Parenthesized expressions
+            Expr::Paren(ParenExpr { expr, .. }) => self.is_safe_constant_for_param_inline(expr),
+
+            _ => false,
+        }
+    }
+
+    /// Compare two optional argument values for equality.
+    /// None represents implicit undefined.
+    fn arg_eq(&self, a: &Option<Box<Expr>>, b: &Option<Box<Expr>>) -> bool {
+        match (a, b) {
+            (None, None) => true, // Both implicit undefined
+            (Some(a_expr), Some(b_expr)) => self.expr_eq(a_expr, b_expr),
+            _ => false, // One is implicit undefined, the other is not
+        }
+    }
+
+    /// Compare two expressions for equality (structural equality for simple
+    /// cases).
+    ///
+    /// We cannot use the derived `Eq` trait because:
+    /// 1. NaN handling: We treat NaN as equal to NaN for parameter inlining
+    ///    purposes, whereas standard floating point comparison has NaN != NaN.
+    /// 2. Context-aware identifier comparison: We only consider unresolved
+    ///    "undefined" identifiers as safe to inline, checking the syntax
+    ///    context.
+    fn expr_eq(&self, a: &Expr, b: &Expr) -> bool {
+        match (a, b) {
+            (Expr::Lit(Lit::Null(_)), Expr::Lit(Lit::Null(_))) => true,
+            (Expr::Lit(Lit::Bool(a)), Expr::Lit(Lit::Bool(b))) => a.value == b.value,
+            (Expr::Lit(Lit::Num(a)), Expr::Lit(Lit::Num(b))) => {
+                // Handle NaN specially: treat NaN as equal to NaN for parameter inlining
+                if a.value.is_nan() && b.value.is_nan() {
+                    true
+                } else {
+                    a.value == b.value
+                }
+            }
+            (Expr::Lit(Lit::Str(a)), Expr::Lit(Lit::Str(b))) => a.value == b.value,
+            (Expr::Lit(Lit::BigInt(a)), Expr::Lit(Lit::BigInt(b))) => a.value == b.value,
+            // Compare identifiers: we can compare naively since is_safe_constant_for_param_inline
+            // already validated that only unresolved "undefined" identifiers reach here
+            (Expr::Ident(a), Expr::Ident(b)) => a.sym == b.sym && a.ctxt == b.ctxt,
+            (
+                Expr::Unary(UnaryExpr {
+                    op: op_a,
+                    arg: arg_a,
+                    ..
+                }),
+                Expr::Unary(UnaryExpr {
+                    op: op_b,
+                    arg: arg_b,
+                    ..
+                }),
+            ) if op_a == op_b => self.expr_eq(arg_a, arg_b),
+            (Expr::Paren(ParenExpr { expr: a, .. }), b) => self.expr_eq(a, b),
+            (a, Expr::Paren(ParenExpr { expr: b, .. })) => self.expr_eq(a, b),
+            _ => false,
+        }
+    }
+
+    /// Remove arguments from a call expression that correspond to inlined
+    /// parameters.
+    ///
+    /// This method should be called when visiting a call expression to ensure
+    /// that arguments are removed for parameters that have been inlined.
+    pub(super) fn remove_inlined_call_args(&mut self, call: &mut CallExpr) {
+        // Get the function identifier from the callee
+        let fn_id = match &call.callee {
+            Callee::Expr(expr) => match &**expr {
+                Expr::Ident(ident) => ident.to_id(),
+                _ => return, // Not a simple identifier call
+            },
+            _ => return,
+        };
+
+        // Check if this function has inlined parameters
+        let inlined_indices = match self.inlined_params.get(&fn_id) {
+            Some(indices) if !indices.is_empty() => indices,
+            _ => return,
+        };
+
+        // Remove arguments at the inlined parameter indices
+        // The indices are already sorted in descending order from apply_param_inlining
+        for &idx in inlined_indices {
+            if idx < call.args.len() {
+                call.args.remove(idx);
+                self.changed = true;
+            }
+        }
+
+        if !inlined_indices.is_empty() {
+            report_change!(
+                "params: Removed {} argument(s) from call to '{}{:?}'",
+                inlined_indices.len(),
+                fn_id.0,
+                fn_id.1
+            );
+        }
+    }
+
+    /// Check if a parameter is shadowed by a function declaration in the
+    /// function body.
+    ///
+    /// This prevents inlining parameters that would conflict with hoisted
+    /// function declarations or var declarations. For example:
+    /// ```js
+    /// function f(a) {
+    ///     function a() { ... }
+    /// }
+    /// function g(arg) {
+    ///     if (condition) {
+    ///         var arg = 2; // var is hoisted and shadows parameter
+    ///     }
+    /// }
+    /// ```
+    /// We cannot inline `a` or `arg` as `let a = value` because the
+    /// declarations are hoisted.
+    fn is_param_shadowed_by_fn_decl(&self, f: &Function, param_id: &Id) -> bool {
+        if let Some(body) = &f.body {
+            self.check_stmts_for_shadowing(&body.stmts, param_id)
+        } else {
+            false
+        }
+    }
+
+    /// Recursively check statements for shadowing declarations.
+    fn check_stmts_for_shadowing(&self, stmts: &[Stmt], param_id: &Id) -> bool {
+        for stmt in stmts {
+            match stmt {
+                // Check for function declarations
+                Stmt::Decl(Decl::Fn(fn_decl)) => {
+                    if fn_decl.ident.to_id() == *param_id {
+                        return true;
+                    }
+                }
+                // Check for var declarations (which are hoisted)
+                Stmt::Decl(Decl::Var(var_decl)) if var_decl.kind == VarDeclKind::Var => {
+                    for decl in &var_decl.decls {
+                        if self.check_pat_for_id(&decl.name, param_id) {
+                            return true;
+                        }
+                    }
+                }
+                // Recursively check block statements
+                Stmt::Block(block) => {
+                    if self.check_stmts_for_shadowing(&block.stmts, param_id) {
+                        return true;
+                    }
+                }
+                // Recursively check if statements
+                Stmt::If(if_stmt) => {
+                    if self.check_stmt_for_shadowing(&if_stmt.cons, param_id) {
+                        return true;
+                    }
+                    if let Some(alt) = &if_stmt.alt {
+                        if self.check_stmt_for_shadowing(alt, param_id) {
+                            return true;
+                        }
+                    }
+                }
+                // Recursively check loops
+                Stmt::While(while_stmt) => {
+                    if self.check_stmt_for_shadowing(&while_stmt.body, param_id) {
+                        return true;
+                    }
+                }
+                Stmt::DoWhile(do_while) => {
+                    if self.check_stmt_for_shadowing(&do_while.body, param_id) {
+                        return true;
+                    }
+                }
+                Stmt::For(for_stmt) => {
+                    // Check init for var declarations
+                    if let Some(init) = &for_stmt.init {
+                        match init {
+                            VarDeclOrExpr::VarDecl(var_decl)
+                                if var_decl.kind == VarDeclKind::Var =>
+                            {
+                                for decl in &var_decl.decls {
+                                    if self.check_pat_for_id(&decl.name, param_id) {
+                                        return true;
+                                    }
+                                }
+                            }
+                            _ => {}
+                        }
+                    }
+                    if self.check_stmt_for_shadowing(&for_stmt.body, param_id) {
+                        return true;
+                    }
+                }
+                Stmt::ForIn(for_in) => {
+                    // Check left side for var declarations
+                    match &for_in.left {
+                        ForHead::VarDecl(var_decl) if var_decl.kind == VarDeclKind::Var => {
+                            for decl in &var_decl.decls {
+                                if self.check_pat_for_id(&decl.name, param_id) {
+                                    return true;
+                                }
+                            }
+                        }
+                        _ => {}
+                    }
+                    if self.check_stmt_for_shadowing(&for_in.body, param_id) {
+                        return true;
+                    }
+                }
+                Stmt::ForOf(for_of) => {
+                    // Check left side for var declarations
+                    match &for_of.left {
+                        ForHead::VarDecl(var_decl) if var_decl.kind == VarDeclKind::Var => {
+                            for decl in &var_decl.decls {
+                                if self.check_pat_for_id(&decl.name, param_id) {
+                                    return true;
+                                }
+                            }
+                        }
+                        _ => {}
+                    }
+                    if self.check_stmt_for_shadowing(&for_of.body, param_id) {
+                        return true;
+                    }
+                }
+                // Recursively check try-catch-finally
+                Stmt::Try(try_stmt) => {
+                    if self.check_stmts_for_shadowing(&try_stmt.block.stmts, param_id) {
+                        return true;
+                    }
+                    if let Some(handler) = &try_stmt.handler {
+                        if self.check_stmts_for_shadowing(&handler.body.stmts, param_id) {
+                            return true;
+                        }
+                    }
+                    if let Some(finalizer) = &try_stmt.finalizer {
+                        if self.check_stmts_for_shadowing(&finalizer.stmts, param_id) {
+                            return true;
+                        }
+                    }
+                }
+                // Recursively check switch statements
+                Stmt::Switch(switch) => {
+                    for case in &switch.cases {
+                        if self.check_stmts_for_shadowing(&case.cons, param_id) {
+                            return true;
+                        }
+                    }
+                }
+                // Recursively check labeled statements
+                Stmt::Labeled(labeled) => {
+                    if self.check_stmt_for_shadowing(&labeled.body, param_id) {
+                        return true;
+                    }
+                }
+                // Recursively check with statements
+                Stmt::With(with) => {
+                    if self.check_stmt_for_shadowing(&with.body, param_id) {
+                        return true;
+                    }
+                }
+                _ => {}
+            }
+        }
+        false
+    }
+
+    /// Helper to check a single statement for shadowing.
+    fn check_stmt_for_shadowing(&self, stmt: &Stmt, param_id: &Id) -> bool {
+        match stmt {
+            Stmt::Block(block) => self.check_stmts_for_shadowing(&block.stmts, param_id),
+            _ => {
+                // For non-block statements, wrap in a slice and check
+                self.check_stmts_for_shadowing(std::slice::from_ref(stmt), param_id)
+            }
+        }
+    }
+
+    /// Check if a pattern contains a specific identifier.
+    fn check_pat_for_id(&self, pat: &Pat, param_id: &Id) -> bool {
+        match pat {
+            Pat::Ident(ident) => ident.id.to_id() == *param_id,
+            Pat::Array(array) => array.elems.iter().any(|elem| {
+                elem.as_ref()
+                    .is_some_and(|e| self.check_pat_for_id(e, param_id))
+            }),
+            Pat::Object(obj) => obj.props.iter().any(|prop| match prop {
+                ObjectPatProp::KeyValue(kv) => self.check_pat_for_id(&kv.value, param_id),
+                ObjectPatProp::Assign(assign) => assign.key.to_id() == *param_id,
+                ObjectPatProp::Rest(rest) => self.check_pat_for_id(&rest.arg, param_id),
+            }),
+            Pat::Rest(rest) => self.check_pat_for_id(&rest.arg, param_id),
+            Pat::Assign(assign) => self.check_pat_for_id(&assign.left, param_id),
+            _ => false,
+        }
+    }
+}
diff --git a/crates/swc_ecma_minifier/src/program_data.rs b/crates/swc_ecma_minifier/src/program_data.rs
index 4f26bb85710e..b1c9d94bc0f2 100644
--- a/crates/swc_ecma_minifier/src/program_data.rs
+++ b/crates/swc_ecma_minifier/src/program_data.rs
@@ -50,6 +50,11 @@ pub(crate) struct ProgramData {
 bitflags::bitflags! {
     #[derive(Debug, Clone, Copy)]
     pub(crate) struct VarUsageInfoFlags: u32 {
+        /// `true` if the variable cannot be safely inlined.
+        /// This is set when the variable is used in contexts that prevent
+        /// inlining optimizations, such as being passed to unknown functions,
+        /// used in complex expressions, or accessed in ways that require
+        /// preserving the original variable binding.
         const INLINE_PREVENTED          = 1 << 0;
         /// `false` if it's only used.
         const DECLARED                  = 1 << 1;
@@ -128,6 +133,13 @@ pub(crate) struct VarUsageInfo {
     infects_to: Vec<Access>,
     /// Only **string** properties.
     pub(crate) accessed_props: FxHashMap<Wtf8Atom, u32>,
+
+    /// Tracks call sites for functions. Each inner Vec contains the arguments
+    /// passed at that call site. Used for parameter inlining optimization.
+    /// Arguments are represented as Option<Box<Expr>> where:
+    /// - Some(expr) = explicit argument passed
+    /// - None = implicit undefined (argument not provided)
+    pub(crate) call_site_args: Option<Vec<Vec<Option<Box<Expr>>>>>,
 }
 
 impl Default for VarUsageInfo {
@@ -146,6 +158,7 @@ impl Default for VarUsageInfo {
             callee_count: Default::default(),
             infects_to: Default::default(),
             accessed_props: Default::default(),
+            call_site_args: Default::default(),
         }
     }
 }
@@ -554,6 +567,20 @@ impl Storage for ProgramData {
     fn get_var_data(&self, id: Id) -> Option<&Self::VarData> {
         self.vars.get(&id).map(|v| v.as_ref())
     }
+
+    fn record_call_site_args(&mut self, callee_id: Id, args: &[Option<Box<Expr>>]) {
+        let var = self.vars.entry(callee_id).or_default();
+
+        // Initialize the call_site_args if it doesn't exist
+        if var.call_site_args.is_none() {
+            var.call_site_args = Some(Vec::new());
+        }
+
+        // Add this call site's arguments (cloned from the slice)
+        if let Some(ref mut call_sites) = var.call_site_args {
+            call_sites.push(args.to_vec());
+        }
+    }
 }
 
 impl ScopeDataLike for ScopeData {
diff --git a/crates/swc_ecma_minifier/tests/benches-full/d3.js b/crates/swc_ecma_minifier/tests/benches-full/d3.js
index 0fbc49a6a3b0..54eb10cd45e5 100644
--- a/crates/swc_ecma_minifier/tests/benches-full/d3.js
+++ b/crates/swc_ecma_minifier/tests/benches-full/d3.js
@@ -2723,10 +2723,10 @@ function(global, factory) {
                 emitter(this, arguments).end(event);
             }).tween("brush", function() {
                 var that = this, state = that.__brush, emit = emitter(that, arguments), selection0 = state.selection, selection1 = dim.input("function" == typeof selection ? selection.apply(this, arguments) : selection, state.extent), i = interpolate(selection0, selection1);
-                function tween(t) {
-                    state.selection = 1 === t && null === selection1 ? null : i(t), redraw.call(that), emit.brush();
+                function tween() {
+                    state.selection = null === selection1 ? null : i(1), redraw.call(that), emit.brush();
                 }
-                return null !== selection0 && null !== selection1 ? tween : tween(1);
+                return null !== selection0 && null !== selection1 ? tween : tween();
             }) : group.each(function() {
                 var args = arguments, state = this.__brush, selection1 = dim.input("function" == typeof selection ? selection.apply(this, args) : selection, state.extent), emit = emitter(this, args).beforestart();
                 interrupt(this), state.selection = null === selection1 ? null : selection1, redraw.call(this), emit.start().brush().end();
@@ -9746,7 +9746,8 @@ function(global, factory) {
         function step() {
             tick(), event.call("tick", simulation), alpha < alphaMin && (stepper.stop(), event.call("end", simulation));
         }
-        function tick(iterations) {
+        function tick() {
+            let iterations;
             var i, node, n = nodes.length;
             void 0 === iterations && (iterations = 1);
             for(var k = 0; k < iterations; ++k)for(alpha += (alphaTarget - alpha) * alphaDecay, forces.forEach(function(force) {
diff --git a/crates/swc_ecma_minifier/tests/benches-full/echarts.js b/crates/swc_ecma_minifier/tests/benches-full/echarts.js
index 3f6bfe43f8bd..abd8027773f2 100644
--- a/crates/swc_ecma_minifier/tests/benches-full/echarts.js
+++ b/crates/swc_ecma_minifier/tests/benches-full/echarts.js
@@ -15928,7 +15928,8 @@
      */ function registerPostUpdate(postUpdateFunc) {
         0 > indexOf(postUpdateFuncs, postUpdateFunc) && postUpdateFunc && postUpdateFuncs.push(postUpdateFunc);
     }
-    function registerAction(actionInfo, eventName, action) {
+    function registerAction(actionInfo, eventName) {
+        let action;
         'function' == typeof eventName && (action = eventName, eventName = '');
         var actionType = isObject$2(actionInfo) ? actionInfo.type : [
             actionInfo,
@@ -33078,7 +33079,7 @@
         });
         group.add(elN), setLargeStyle$1(1, elP, seriesModel), setLargeStyle$1(-1, elN, seriesModel), incremental && (elP.incremental = !0, elN.incremental = !0);
     }
-    function setLargeStyle$1(sign, el, seriesModel, data) {
+    function setLargeStyle$1(sign, el, seriesModel) {
         // TODO put in visual?
         var borderColor = seriesModel.get([
             'itemStyle',
@@ -35529,7 +35530,8 @@
                 });
             }
             return result;
-        }(_a[0], _a[1], 0, Math.PI), isIndividualMorphingPath(toPath) || (toPath.__oldBuildPath = toPath.buildPath, toPath.buildPath = morphingPathBuildPath), function(morphingPath, morphingData, morphT) {
+        }(_a[0], _a[1], 0, Math.PI), isIndividualMorphingPath(toPath) || (toPath.__oldBuildPath = toPath.buildPath, toPath.buildPath = morphingPathBuildPath), function(morphingPath, morphingData) {
+            let morphT = 0;
             morphingPath.__morphingData = morphingData, morphingPath.__morphT = morphT;
         }(toPath, morphingData, 0);
         var oldDone = animationOpts && animationOpts.done, oldAborted = animationOpts && animationOpts.aborted, oldDuring = animationOpts && animationOpts.during;
@@ -36328,13 +36330,15 @@
             txCfgOpt && (stateObj.textConfig = txCfgOpt), setDefaultStateProxy(elDisplayable);
         }
     }
-    function setLagecyTransformProp(elOption, targetProps, legacyName, fromTransformable // If provided, retrieve from the element.
-    ) {
+    function setLagecyTransformProp(elOption, targetProps, legacyName) {
+        let fromTransformable // If provided, retrieve from the element.
+        ;
         var legacyArr = elOption[legacyName], xyName = LEGACY_TRANSFORM_PROPS[legacyName];
         legacyArr && (fromTransformable ? (targetProps[xyName[0]] = fromTransformable[xyName[0]], targetProps[xyName[1]] = fromTransformable[xyName[1]]) : (targetProps[xyName[0]] = legacyArr[0], targetProps[xyName[1]] = legacyArr[1]));
     }
-    function setTransformProp(elOption, allProps, name, fromTransformable // If provided, retrieve from the element.
-    ) {
+    function setTransformProp(elOption, allProps, name) {
+        let fromTransformable // If provided, retrieve from the element.
+        ;
         null != elOption[name] && (allProps[name] = fromTransformable ? fromTransformable[name] : elOption[name]);
     }
     function setTransformPropToTransitionFrom(transitionFrom, name, fromTransformable // If provided, retrieve from the element.
diff --git a/crates/swc_ecma_minifier/tests/benches-full/lodash.js b/crates/swc_ecma_minifier/tests/benches-full/lodash.js
index 8adbfc500bd5..2ee12dabea76 100644
--- a/crates/swc_ecma_minifier/tests/benches-full/lodash.js
+++ b/crates/swc_ecma_minifier/tests/benches-full/lodash.js
@@ -6014,7 +6014,8 @@
      *
      * _.words('fred, barney, & pebbles', /[^, ]+/g);
      * // => ['fred', 'barney', '&', 'pebbles']
-     */ function words(string, pattern, guard) {
+     */ function words(string) {
+            let pattern, guard;
             if (string = toString(string), pattern = guard ? undefined : pattern, undefined === pattern) {
                 var string1;
                 return (string1 = string, reHasUnicodeWord.test(string1)) ? string.match(reUnicodeWord) || [] : string.match(reAsciiWord) || [];
diff --git a/crates/swc_ecma_minifier/tests/benches-full/terser.js b/crates/swc_ecma_minifier/tests/benches-full/terser.js
index 90ec0ed29931..1e1288b90008 100644
--- a/crates/swc_ecma_minifier/tests/benches-full/terser.js
+++ b/crates/swc_ecma_minifier/tests/benches-full/terser.js
@@ -1047,7 +1047,8 @@
             }
             unexpected();
         });
-        function simple_statement(tmp) {
+        function simple_statement() {
+            let tmp;
             return new AST_SimpleStatement({
                 body: (tmp = expression(!0), semicolon(), tmp)
             });
diff --git a/crates/swc_ecma_minifier/tests/benches-full/three.js b/crates/swc_ecma_minifier/tests/benches-full/three.js
index d4566afd30f6..0e5ada6cb398 100644
--- a/crates/swc_ecma_minifier/tests/benches-full/three.js
+++ b/crates/swc_ecma_minifier/tests/benches-full/three.js
@@ -6589,8 +6589,8 @@ function(global, factory) {
         function setFlipSided(flipSided) {
             currentFlipSided !== flipSided && (flipSided ? gl.frontFace(2304) : gl.frontFace(2305), currentFlipSided = flipSided);
         }
-        function setCullFace(cullFace) {
-            0 !== cullFace ? (enable(2884), cullFace !== currentCullFace && (1 === cullFace ? gl.cullFace(1029) : 2 === cullFace ? gl.cullFace(1028) : gl.cullFace(1032))) : disable(2884), currentCullFace = cullFace;
+        function setCullFace() {
+            enable(2884), 1 !== currentCullFace && gl.cullFace(1029), currentCullFace = 1;
         }
         function setPolygonOffset(polygonOffset, factor, units) {
             polygonOffset ? (enable(32823), (currentPolygonOffsetFactor !== factor || currentPolygonOffsetUnits !== units) && (gl.polygonOffset(factor, units), currentPolygonOffsetFactor = factor, currentPolygonOffsetUnits = units)) : disable(32823);
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/10328/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/10328/output.js
index 27816b6a1ed4..45211a8b6ab8 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/10328/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/10328/output.js
@@ -1,4 +1,4 @@
-function g(x, v) {
+function g(x) {
     if ("a" === x) {
         let h;
         h = i({
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/10473/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/10473/output.js
index 2fc970d2e611..5c9df8bb8a9a 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/10473/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/10473/output.js
@@ -18,11 +18,11 @@ function _objectSpread(t) {
         e % 2 ? ownKeys(Object(o), !0).forEach(function(e) {
             !function(e, t, o) {
                 var e1;
-                (e1 = function(e, t) {
+                (e1 = function(e) {
                     if ("object" != _typeof(e) || !e) return e;
                     var o = e[Symbol.toPrimitive];
-                    if (void 0 === o) return ("string" === t ? String : Number)(e);
-                    if (o = o.call(e, t || "default"), "object" != _typeof(o)) return o;
+                    if (void 0 === o) return String(e);
+                    if (o = o.call(e, "string"), "object" != _typeof(o)) return o;
                     throw TypeError("@@toPrimitive must return a primitive value.");
                 }(e1 = t, "string"), (t = "symbol" == _typeof(e1) ? e1 : e1 + "") in e) ? Object.defineProperty(e, t, {
                     value: o,
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/2044/full/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/2044/full/output.js
index e18cbc495996..d94a7c316add 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/2044/full/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/2044/full/output.js
@@ -21,7 +21,8 @@ createCommonjsModule(function(module, exports) {
         value: !0
     });
 }), createCommonjsModule(function(module, exports) {
-    function _interopRequireDefault(obj) {
+    function _interopRequireDefault() {
+        let obj;
         return obj && obj.__esModule ? obj : {
             default: obj
         };
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-1/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-1/output.js
index e3bd904d61f9..7f90a5187591 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-1/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-1/output.js
@@ -19,7 +19,8 @@ createCommonjsModule(function(module, exports) {
         value: !0
     });
 }), createCommonjsModule(function(module, exports) {
-    function _interopRequireDefault(obj) {
+    function _interopRequireDefault() {
+        let obj;
         return obj && obj.__esModule ? obj : {
             default: obj
         };
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-10/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-10/output.js
index e3bd904d61f9..7f90a5187591 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-10/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/2044/pass-10/output.js
@@ -19,7 +19,8 @@ createCommonjsModule(function(module, exports) {
         value: !0
     });
 }), createCommonjsModule(function(module, exports) {
-    function _interopRequireDefault(obj) {
+    function _interopRequireDefault() {
+        let obj;
         return obj && obj.__esModule ? obj : {
             default: obj
         };
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/8813/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/8813/output.js
index 618b0354a8c7..01288398b039 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/8813/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/8813/output.js
@@ -1,4 +1,4 @@
-let x = 'asdf', y = "PASS 1";
+let NaN, x = 'asdf', y = "PASS 1";
 switch(x){
     case x:
     default:
@@ -21,7 +21,7 @@ var c = "FAIL";
 switch(0 / 0){
     case 0 / 0:
         break;
-    case void (c = "PASS"):
+    case c = "PASS", NaN:
         c = "FAIL";
 }
 console.log(c);
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/firebase/dist/1/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/firebase/dist/1/output.js
index f8d2531807bd..ca9b2bd71a13 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/firebase/dist/1/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/firebase/dist/1/output.js
@@ -1,4 +1,5 @@
 "use strict";
+let variant;
 var _a, util = require("@firebase/util"), tslib = require("tslib"), component = require("@firebase/component"), modularAPIs = require("@firebase/app"), logger$1 = require("@firebase/logger"), modularAPIs__namespace = /*#__PURE__*/ function(e) {
     if (e && e.__esModule) return e;
     var n = Object.create(null);
@@ -278,5 +279,5 @@ if (util.isBrowser() && void 0 !== self.firebase) {
     sdkVersion && sdkVersion.indexOf("LITE") >= 0 && logger.warn("\n    Warning: You are trying to load Firebase while using Firebase Performance standalone script.\n    You should load Firebase Performance with this instance of Firebase to avoid loading duplicate code.\n    ");
 }
 // Register `app` package.
-modularAPIs.registerVersion("@firebase/app-compat", "0.1.5", void 0), module.exports = firebase$1;
+modularAPIs.registerVersion("@firebase/app-compat", "0.1.5", variant), module.exports = firebase$1;
  //# sourceMappingURL=index.cjs.js.map
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/quagga2/1.4.2/1/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/quagga2/1.4.2/1/output.js
index fb2d94c1a06b..750c6172be86 100644
--- a/crates/swc_ecma_minifier/tests/fixture/issues/quagga2/1.4.2/1/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/quagga2/1.4.2/1/output.js
@@ -8659,10 +8659,10 @@
                                 if (0xff !== dataView.getUint8(0) || 0xd8 !== dataView.getUint8(1)) return !1;
                                 for(; offset < length && 0xff === dataView.getUint8(offset);){
                                     if (0xe1 === dataView.getUint8(offset + 1)) return function(file, start, exifTags) {
-                                        if ("Exif" !== function(buffer, start, length) {
+                                        if ("Exif" !== function(buffer, start) {
                                             for(var outstr = "", n = start; n < start + 4; n++)outstr += String.fromCharCode(buffer.getUint8(n));
                                             return outstr;
-                                        }(file, start, 0)) return !1;
+                                        }(file, start, 4)) return !1;
                                         var bigEnd, tiffOffset = start + 6;
                                         if (0x4949 === file.getUint16(tiffOffset)) bigEnd = !1;
                                         else {
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/d6e1aeb5-38a8d7ae57119c23/output.js b/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/d6e1aeb5-38a8d7ae57119c23/output.js
index aeb74976e398..80f56034403e 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/d6e1aeb5-38a8d7ae57119c23/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/d6e1aeb5-38a8d7ae57119c23/output.js
@@ -24320,9 +24320,10 @@
                     this.trigger("dispose"), this.pendingTimelineChanges_ = {}, this.lastTimelineChanges_ = {}, this.off();
                 }, TimelineChangeController;
             }(videojs.EventTarget), Decrypter = factory(transform(getWorkerString(function() {
-                function createCommonjsModule(fn, basedir, module) {
+                function createCommonjsModule(fn) {
+                    let module;
                     return fn(module = {
-                        path: basedir,
+                        path: void 0,
                         exports: {},
                         require: function(path, base) {
                             throw null == base && module.path, Error("Dynamic requires are not currently supported by @rollup/plugin-commonjs");
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js b/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js
index d6dc0a8d4302..f5fdec7d9d7b 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js
@@ -1033,7 +1033,8 @@
              * @returns {Readonly<T>}
              *
              * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze
-             */ function freeze(object, oc) {
+             */ function freeze(object) {
+                let oc;
                 return void 0 === oc && (oc = Object), oc && "function" == typeof oc.freeze ? oc.freeze(object) : object;
             }
             /**
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/36127/2/2/output.js b/crates/swc_ecma_minifier/tests/fixture/next/36127/2/2/output.js
index 111142aa0cbf..1f8dc4931b59 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/36127/2/2/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/36127/2/2/output.js
@@ -3,14 +3,14 @@
  *
  * @param {RegExp} regex
  * @returns {(code: Code) => code is number}
- */ function regexCheck(regex) {
+ */ function regexCheck() {
     return(/**
      * Check whether a code matches the bound regex.
      *
      * @param {Code} code Character code
      * @returns {code is number} Whether the character code matches the bound regex
      */ function(code) {
-        return null !== code && regex.test(String.fromCharCode(code));
+        return null !== code && "Foo".test(String.fromCharCode(code));
     });
 }
-console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo")), console.log(regexCheck("Foo"));
+console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck()), console.log(regexCheck());
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/chakra/output.js b/crates/swc_ecma_minifier/tests/fixture/next/chakra/output.js
index 6e7e09e57b0e..5f86c614ae60 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/chakra/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/chakra/output.js
@@ -1548,7 +1548,8 @@
                 var value1, replaceValue, valueStr = (value1 = value.toString(), void 0 === replaceValue && (replaceValue = "-"), value1.replace(/\s+/g, replaceValue));
                 return valueStr.includes("\\.") || Number.isInteger(parseFloat(value.toString())) ? value : valueStr.replace(".", "\\.");
             }
-            function cssVar(name, options) {
+            function cssVar(name) {
+                let options;
                 var fallback, prefix, prefix1, fallback1, cssVariable = (void 0 === (prefix = null == options ? void 0 : options.prefix) && (prefix = ""), "--" + (void 0 === (prefix1 = prefix) && (prefix1 = ""), [
                     prefix1,
                     chakra_ui_theme_tools_esm_escape(name)
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/react-ace/chunks/8a28b14e.d8fbda268ed281a1/output.js b/crates/swc_ecma_minifier/tests/fixture/next/react-ace/chunks/8a28b14e.d8fbda268ed281a1/output.js
index 4702ca507806..1a1ed8a812cf 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/react-ace/chunks/8a28b14e.d8fbda268ed281a1/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/react-ace/chunks/8a28b14e.d8fbda268ed281a1/output.js
@@ -156,7 +156,8 @@
                         importCssString(item[0], item[1]);
                     });
                 }
-                function importCssString(cssText, id, target) {
+                function importCssString(cssText, id) {
+                    let target;
                     if ("undefined" != typeof document) {
                         if (cssCache) {
                             if (target) insertPendingStyles();
@@ -1806,9 +1807,9 @@
                 var reportErrorIfPathIsNotConfigured = function() {
                     options.basePath || options.workerPath || options.modePath || options.themePath || Object.keys(options.$moduleUrls).length || (console.error("Unable to infer path to ace from script src,", "use ace.config.set('basePath', 'path') to enable dynamic loading of modes and themes", "or with webpack use ace/webpack-resolver"), reportErrorIfPathIsNotConfigured = function() {});
                 };
-                function init(packaged) {
+                function init() {
                     if (global && global.document) {
-                        options.packaged = packaged || require.packaged || module.packaged || global.define && __webpack_require__.amdD.packaged;
+                        options.packaged = !0;
                         for(var scriptOptions = {}, scriptUrl = "", currentScript = document.currentScript || document._currentScript, scripts = (currentScript && currentScript.ownerDocument || document).getElementsByTagName("script"), i = 0; i < scripts.length; i++){
                             var script = scripts[i], src = script.src || script.getAttribute("src");
                             if (src) {
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/react-pdf-renderer/output.js b/crates/swc_ecma_minifier/tests/fixture/next/react-pdf-renderer/output.js
index 30e171b619b2..feaeb167379f 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/react-pdf-renderer/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/react-pdf-renderer/output.js
@@ -21785,10 +21785,11 @@
                     function o(e) {
                         var t = this;
                         this.next = null, this.entry = null, this.finish = function() {
-                            var r = t.entry;
-                            for(t.entry = null; r;){
-                                var n = r.callback;
-                                e.pendingcb--, n(void 0), r = r.next;
+                            let r;
+                            var n = t.entry;
+                            for(t.entry = null; n;){
+                                var i = n.callback;
+                                e.pendingcb--, i(r), n = n.next;
                             }
                             e.corkedRequestsFree.next = t;
                         };
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/syncfusion/933-e9f9a6bf671b96fc/output.js b/crates/swc_ecma_minifier/tests/fixture/next/syncfusion/933-e9f9a6bf671b96fc/output.js
index a8d36837dd8f..3c908ce02b77 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/syncfusion/933-e9f9a6bf671b96fc/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/syncfusion/933-e9f9a6bf671b96fc/output.js
@@ -7773,7 +7773,8 @@
      * @param {Element[] | NodeList} elements - The elements which are needed to add / remove classes.
      * @param {string} oldClass
      * - Css class names which are needed to remove. If old classes are need to remove, can give this optional parameter.
-     */ function setCssClass(cssClass, elements, oldClass) {
+     */ function setCssClass(cssClass, elements) {
+                    let oldClass;
                     (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .isNullOrUndefined */ .le)(oldClass) || '' === oldClass || (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .removeClass */ .IV)(elements, oldClass.split(' ')), (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .isNullOrUndefined */ .le)(cssClass) || '' === cssClass || (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .addClass */ .cn)(elements, cssClass.split(' '));
                 }
                 /**
@@ -7813,7 +7814,8 @@
      * - Boolean value to specify whether to set read only. Setting "True" value enables read only.
      * @param {HTMLInputElement | HTMLTextAreaElement} element
      * - The element which is need to enable read only.
-     */ function setReadonly(isReadonly, element, floatLabelType) {
+     */ function setReadonly(isReadonly, element) {
+                    let floatLabelType;
                     isReadonly ? (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .attributes */ .Y4)(element, {
                         readonly: ''
                     }) : element.removeAttribute('readonly'), (0, _syncfusion_ej2_base__WEBPACK_IMPORTED_MODULE_0__ /* .isNullOrUndefined */ .le)(floatLabelType) || validateLabel(element, floatLabelType);
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/target-es2015/static/chunks/main-04b5934c26266542/output.js b/crates/swc_ecma_minifier/tests/fixture/next/target-es2015/static/chunks/main-04b5934c26266542/output.js
index e3bc766d1c37..3cd68e58a2b3 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/target-es2015/static/chunks/main-04b5934c26266542/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/target-es2015/static/chunks/main-04b5934c26266542/output.js
@@ -928,7 +928,8 @@
                     throw map.delete(key), err;
                 }) : prom;
             }
-            let canPrefetch = function(link) {
+            let canPrefetch = function() {
+                let link;
                 try {
                     return link = document.createElement("link"), !!window.MSInputMethodContext && !!document.documentMode || link.relList.supports("prefetch");
                 } catch (e) {
diff --git a/crates/swc_ecma_minifier/tests/fixture/next/wrap-contracts/output.js b/crates/swc_ecma_minifier/tests/fixture/next/wrap-contracts/output.js
index 74c804daa064..c3a45084d147 100644
--- a/crates/swc_ecma_minifier/tests/fixture/next/wrap-contracts/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/next/wrap-contracts/output.js
@@ -19850,7 +19850,8 @@
                         function endWritable(e, t, r) {
                             t.ending = !0, finishMaybe(e, t), r && (t.finished ? process.nextTick(r) : e.once("finish", r)), t.ended = !0, e.writable = !1;
                         }
-                        function onCorkedFinish(e, t, r) {
+                        function onCorkedFinish(e, t) {
+                            let r;
                             var n = e.entry;
                             for(e.entry = null; n;){
                                 var i = n.callback;
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/config.json
new file mode 100644
index 000000000000..ea4efc8d6d6b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/config.json
@@ -0,0 +1,3 @@
+{
+  "inline": 2
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/input.js
new file mode 100644
index 000000000000..e42612b0b0d5
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/input.js
@@ -0,0 +1,11 @@
+// Arrow function with inlinable parameter
+const process = (value, multiplier) => {
+  return value * multiplier;
+};
+
+// multiplier is always 2
+const result1 = process(10, 2);
+const result2 = process(20, 2);
+const result3 = process(30, 2);
+
+console.log(result1, result2, result3);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/output.js
new file mode 100644
index 000000000000..5ed281a587fd
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/arrow_function/output.js
@@ -0,0 +1,7 @@
+// Arrow function with inlinable parameter
+const process = (value, multiplier)=>value * multiplier;
+// multiplier is always 2
+const result1 = 20;
+const result2 = 40;
+const result3 = 60;
+console.log(20, 40, 60);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/config.json
new file mode 100644
index 000000000000..dc43e1ae5d1f
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/config.json
@@ -0,0 +1,4 @@
+{
+  "inline": 2,
+  "reduce_vars": true
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/input.js
new file mode 100644
index 000000000000..7889be21e9f7
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/input.js
@@ -0,0 +1,9 @@
+// Basic parameter inlining - undefined parameter
+function complex(foo, fn) {
+  if (Math.random() > 0.5) throw new Error();
+  return fn?.(foo);
+}
+
+console.log(complex("foo"));
+console.log(complex("bar"));
+console.log(complex("baz"));
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/output.js
new file mode 100644
index 000000000000..8d3fa6f65387
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/basic/output.js
@@ -0,0 +1,9 @@
+// Basic parameter inlining - undefined parameter
+function complex(foo) {
+    let fn;
+    if (Math.random() > 0.5) throw Error();
+    return fn?.(foo);
+}
+console.log(complex("foo"));
+console.log(complex("bar"));
+console.log(complex("baz"));
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/config.json
new file mode 100644
index 000000000000..ea4efc8d6d6b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/config.json
@@ -0,0 +1,3 @@
+{
+  "inline": 2
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/input.js
new file mode 100644
index 000000000000..d72a4eda6b21
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/input.js
@@ -0,0 +1,8 @@
+// Should NOT inline - different values passed
+function add(a, b) {
+  return a + b;
+}
+
+console.log(add(1, 2));
+console.log(add(3, 4));
+console.log(add(5, 6));
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/output.js
new file mode 100644
index 000000000000..54e25bd81b95
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/different_values/output.js
@@ -0,0 +1,7 @@
+// Should NOT inline - different values passed
+function add(a, b) {
+    return a + b;
+}
+console.log(add(1, 2));
+console.log(add(3, 4));
+console.log(add(5, 6));
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/config.json
new file mode 100644
index 000000000000..ea4efc8d6d6b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/config.json
@@ -0,0 +1,3 @@
+{
+  "inline": 2
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/input.js
new file mode 100644
index 000000000000..e9b2f6e15713
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/input.js
@@ -0,0 +1,9 @@
+// Various literal types that can be inlined
+function literals(str, num, bool, nil) {
+  console.log(str, num, bool, nil);
+  return str + num;
+}
+
+literals("hello", 42, true, null);
+literals("hello", 42, true, null);
+literals("hello", 42, true, null);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/output.js
new file mode 100644
index 000000000000..dfd98a9e4e79
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/literal_values/output.js
@@ -0,0 +1,9 @@
+// Various literal types that can be inlined
+function literals() {
+    let str = "hello";
+    console.log(str, 42, true, null);
+    return str + 42;
+}
+literals();
+literals();
+literals();
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/config.json
new file mode 100644
index 000000000000..ea4efc8d6d6b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/config.json
@@ -0,0 +1,3 @@
+{
+  "inline": 2
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/input.js
new file mode 100644
index 000000000000..c87a0739900a
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/input.js
@@ -0,0 +1,12 @@
+// Mixed parameters - some inlinable, some not
+function mixed(foo, callback, debug) {
+  if (debug) {
+    console.log("Debug:", foo);
+  }
+  return callback(foo);
+}
+
+// callback varies, debug is always undefined
+mixed("a", x => x * 2);
+mixed("b", x => x + 1);
+mixed("c", x => x - 1);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/output.js
new file mode 100644
index 000000000000..b2dc37a6580b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/mixed_params/output.js
@@ -0,0 +1,10 @@
+// Mixed parameters - some inlinable, some not
+function mixed(foo, callback) {
+    let debug;
+    if (debug) console.log("Debug:", foo);
+    return callback(foo);
+}
+// callback varies, debug is always undefined
+mixed("a", (x)=>2 * x);
+mixed("b", (x)=>x + 1);
+mixed("c", (x)=>x - 1);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/config.json b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/config.json
new file mode 100644
index 000000000000..ea4efc8d6d6b
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/config.json
@@ -0,0 +1,3 @@
+{
+  "inline": 2
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/input.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/input.js
new file mode 100644
index 000000000000..c7e22c131ab3
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/input.js
@@ -0,0 +1,9 @@
+// Multiple parameters that can all be inlined
+function calc(a, b, c) {
+  return a + b + c;
+}
+
+// All parameters are consistently the same
+calc(1, 2, 3);
+calc(1, 2, 3);
+calc(1, 2, 3);
diff --git a/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/output.js b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/output.js
new file mode 100644
index 000000000000..d1624865b693
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/param_inline/multiple_params/output.js
@@ -0,0 +1,8 @@
+// Multiple parameters that can all be inlined
+function calc() {
+    return 6;
+}
+// All parameters are consistently the same
+calc();
+calc();
+calc();
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/chunkfilename-b114cf1d23876beaa712/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/chunkfilename-b114cf1d23876beaa712/output.js
index bd88212357bd..9f40e6633f21 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/chunkfilename-b114cf1d23876beaa712/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/chunkfilename-b114cf1d23876beaa712/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/function-7fe8439c89afccb77983/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/function-7fe8439c89afccb77983/output.js
index 13c9f3d00838..4387aa2f0929 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/function-7fe8439c89afccb77983/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/function-7fe8439c89afccb77983/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/head-432fc3a9a66c90ce2ec2/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/head-432fc3a9a66c90ce2ec2/output.js
index dea558eeb324..22eae434f1f7 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/head-432fc3a9a66c90ce2ec2/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/head-432fc3a9a66c90ce2ec2/output.js
@@ -239,12 +239,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/multiple-modules-d02ebebcfa5282e50b34/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/multiple-modules-d02ebebcfa5282e50b34/output.js
index 0f2aa788296a..e180e3f7b64f 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/multiple-modules-d02ebebcfa5282e50b34/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/multiple-modules-d02ebebcfa5282e50b34/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/nested-05a7ce04b1f7eb6da341/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/nested-05a7ce04b1f7eb6da341/output.js
index 12b8a73bf19d..b2d51f0b9f29 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/nested-05a7ce04b1f7eb6da341/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/nested-05a7ce04b1f7eb6da341/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-chunk-e2d9573b8d7df68a6cde/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-chunk-e2d9573b8d7df68a6cde/output.js
index 192d61118060..39949be8b45f 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-chunk-e2d9573b8d7df68a6cde/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-chunk-e2d9573b8d7df68a6cde/output.js
@@ -321,12 +321,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-9ced90e71a0d75a11cdd/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-9ced90e71a0d75a11cdd/output.js
index 8c3d1fd81382..b1f71fa2826b 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-9ced90e71a0d75a11cdd/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-9ced90e71a0d75a11cdd/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-custom-loading-7f61b2e27708ca1854e0/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-custom-loading-7f61b2e27708ca1854e0/output.js
index a8d0fa08983e..3a4e1a4895d7 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-custom-loading-7f61b2e27708ca1854e0/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/no-ssr-custom-loading-7f61b2e27708ca1854e0/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-994266264fb6ff57d32c/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-994266264fb6ff57d32c/output.js
index 5749de67698c..2173017613d2 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-994266264fb6ff57d32c/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-994266264fb6ff57d32c/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-true-6d4aa8fc503b9d073aef/output.js b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-true-6d4aa8fc503b9d073aef/output.js
index def8deb09cd5..d2dcadfe9f93 100644
--- a/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-true-6d4aa8fc503b9d073aef/output.js
+++ b/crates/swc_ecma_minifier/tests/fixture/projects/next/archive-3/pages/dynamic/ssr-true-6d4aa8fc503b9d073aef/output.js
@@ -207,12 +207,13 @@
                         READY_INITIALIZERS.push(function(ids) {
                             var _step, _iterator = function(o, allowArrayLike) {
                                 if ("undefined" == typeof Symbol || null == o[Symbol.iterator]) {
-                                    if (Array.isArray(o) || (it = function(o, minLen) {
+                                    if (Array.isArray(o) || (it = function(o) {
+                                        let minLen;
                                         if (o) {
-                                            if ("string" == typeof o) return _arrayLikeToArray(o, void 0);
+                                            if ("string" == typeof o) return _arrayLikeToArray(o, minLen);
                                             var n = Object.prototype.toString.call(o).slice(8, -1);
                                             if ("Object" === n && o.constructor && (n = o.constructor.name), "Map" === n || "Set" === n) return Array.from(o);
-                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, void 0);
+                                            if ("Arguments" === n || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
                                         }
                                     }(o))) {
                                         it && (o = it);
diff --git a/crates/swc_ecma_minifier/tests/libs-size.snapshot.md b/crates/swc_ecma_minifier/tests/libs-size.snapshot.md
index 561c402979ab..33def784d1a5 100644
--- a/crates/swc_ecma_minifier/tests/libs-size.snapshot.md
+++ b/crates/swc_ecma_minifier/tests/libs-size.snapshot.md
@@ -1,14 +1,14 @@
 | File | Original Size | Compressed Size | Gzipped Size |
 | --- | --- | --- | --- |
 | antd.js | 6.38 MiB | 2.06 MiB | 445.40 KiB |
-| d3.js | 542.74 KiB | 261.45 KiB | 85.34 KiB |
-| echarts.js | 3.41 MiB | 977.31 KiB | 314.18 KiB |
+| d3.js | 542.74 KiB | 261.44 KiB | 85.33 KiB |
+| echarts.js | 3.41 MiB | 977.32 KiB | 314.19 KiB |
 | jquery.js | 280.89 KiB | 87.80 KiB | 30.21 KiB |
 | lodash.js | 531.35 KiB | 68.92 KiB | 24.60 KiB |
 | moment.js | 169.83 KiB | 57.39 KiB | 18.26 KiB |
 | react.js | 70.45 KiB | 22.44 KiB | 8.04 KiB |
-| terser.js | 1.08 MiB | 446.65 KiB | 120.49 KiB |
-| three.js | 1.19 MiB | 630.73 KiB | 154.79 KiB |
-| typescript.js | 10.45 MiB | 3.17 MiB | 840.60 KiB |
+| terser.js | 1.08 MiB | 446.66 KiB | 120.48 KiB |
+| three.js | 1.19 MiB | 630.72 KiB | 154.79 KiB |
+| typescript.js | 10.45 MiB | 3.17 MiB | 840.69 KiB |
 | victory.js | 2.30 MiB | 694.10 KiB | 154.19 KiB |
 | vue.js | 334.13 KiB | 113.70 KiB | 41.81 KiB |
diff --git a/crates/swc_ecma_minifier/tests/pass-1/9/1/output.js b/crates/swc_ecma_minifier/tests/pass-1/9/1/output.js
index 543a8daa637c..6d837d2a0610 100644
--- a/crates/swc_ecma_minifier/tests/pass-1/9/1/output.js
+++ b/crates/swc_ecma_minifier/tests/pass-1/9/1/output.js
@@ -1 +1,4 @@
-console.log("Greeting:", "Hello");
+let value;
+console.log("Greeting:", (value = "Hello", function() {
+    return value;
+})());
diff --git a/crates/swc_ecma_minifier/tests/projects-size.snapshot.md b/crates/swc_ecma_minifier/tests/projects-size.snapshot.md
index 9a6f8ecf5eea..625b3dcfdf41 100644
--- a/crates/swc_ecma_minifier/tests/projects-size.snapshot.md
+++ b/crates/swc_ecma_minifier/tests/projects-size.snapshot.md
@@ -2,7 +2,7 @@
 | --- | --- | --- | --- |
 | angular-1.2.5.js | 757.44 KiB | 101.91 KiB | 37.18 KiB |
 | backbone-1.1.0.js | 59.77 KiB | 18.33 KiB | 6.29 KiB |
-| jquery-1.9.1.js | 309.61 KiB | 90.76 KiB | 32.09 KiB |
+| jquery-1.9.1.js | 309.61 KiB | 90.78 KiB | 32.08 KiB |
 | jquery.mobile-1.4.2.js | 534.38 KiB | 191.23 KiB | 52.60 KiB |
 | mootools-1.4.5.js | 181.36 KiB | 88.54 KiB | 27.48 KiB |
 | react-17.0.1.js | 82.58 KiB | 22.44 KiB | 8.04 KiB |
diff --git a/crates/swc_ecma_minifier/tests/projects/output/jquery-1.9.1.js b/crates/swc_ecma_minifier/tests/projects/output/jquery-1.9.1.js
index 1cc607d293b4..cb0368895520 100644
--- a/crates/swc_ecma_minifier/tests/projects/output/jquery-1.9.1.js
+++ b/crates/swc_ecma_minifier/tests/projects/output/jquery-1.9.1.js
@@ -2734,7 +2734,7 @@
         domManip: function(args, table, callback) {
             // Flatten any nested arrays
             args = core_concat.apply([], args);
-            var elem, tag, first, node, hasScripts, scripts, doc, fragment, i = 0, l = this.length, set = this, iNoClone = l - 1, value = args[0], isFunction = jQuery.isFunction(value);
+            var first, node, hasScripts, scripts, doc, fragment, i = 0, l = this.length, set = this, iNoClone = l - 1, value = args[0], isFunction = jQuery.isFunction(value);
             // We can't cloneNode fragments that contain checked, in WebKit
             if (isFunction || !(l <= 1 || "string" != typeof value || jQuery.support.checkClone || !rchecked.test(value))) return this.each(function(index) {
                 var self = set.eq(index);
@@ -2743,9 +2743,10 @@
             if (l && (first = (fragment = jQuery.buildFragment(args, this[0].ownerDocument, !1, this)).firstChild, 1 === fragment.childNodes.length && (fragment = first), first)) {
                 // Use the original fragment for the last item instead of the first because it can end up
                 // being emptied incorrectly in certain situations (#8070).
-                for(table = table && jQuery.nodeName(first, "tr"), hasScripts = (scripts = jQuery.map(getAll(fragment, "script"), disableScript)).length; i < l; i++){
-                    node = fragment, i !== iNoClone && (node = jQuery.clone(node, !0, !0), hasScripts && jQuery.merge(scripts, getAll(node, "script"))), callback.call(table && jQuery.nodeName(this[i], "table") ? (elem = this[i], tag = "tbody", elem.getElementsByTagName(tag)[0] || elem.appendChild(elem.ownerDocument.createElement(tag))) : this[i], node, i);
-                }
+                for(table = table && jQuery.nodeName(first, "tr"), hasScripts = (scripts = jQuery.map(getAll(fragment, "script"), disableScript)).length; i < l; i++)node = fragment, i !== iNoClone && (node = jQuery.clone(node, !0, !0), hasScripts && jQuery.merge(scripts, getAll(node, "script"))), callback.call(table && jQuery.nodeName(this[i], "table") ? function(elem) {
+                    let tag = "tbody";
+                    return elem.getElementsByTagName(tag)[0] || elem.appendChild(elem.ownerDocument.createElement(tag));
+                }(this[i], "tbody") : this[i], node, i);
                 if (hasScripts) // Evaluate executable scripts on first document insertion
                 for(doc = scripts[scripts.length - 1].ownerDocument, // Reenable scripts
                 jQuery.map(scripts, restoreScript), i = 0; i < hasScripts; i++)node = scripts[i], rscriptType.test(node.type || "") && !jQuery._data(node, "globalEval") && jQuery.contains(doc, node) && (node.src ? // Hope ajax is available...
diff --git a/crates/swc_ecma_minifier/tests/projects/output/react-dom-17.0.2.js b/crates/swc_ecma_minifier/tests/projects/output/react-dom-17.0.2.js
index 63e6271ebb28..2de27d204873 100644
--- a/crates/swc_ecma_minifier/tests/projects/output/react-dom-17.0.2.js
+++ b/crates/swc_ecma_minifier/tests/projects/output/react-dom-17.0.2.js
@@ -3377,9 +3377,9 @@
    * @return {boolean} True if the event is supported.
    * @internal
    * @license Modernizr 3.0.0pre (Custom Build) | MIT
-   */ function(eventNameSuffix) {
+   */ function() {
         if (!canUseDOM) return !1;
-        var eventName = "on" + eventNameSuffix, isSupported = eventName in document;
+        var eventName = "oninput", isSupported = eventName in document;
         if (!isSupported) {
             var element = document.createElement("div");
             element.setAttribute(eventName, "return;"), isSupported = "function" == typeof element[eventName];
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/arrow/issue_2136_2/output.js b/crates/swc_ecma_minifier/tests/terser/compress/arrow/issue_2136_2/output.js
index 3bae317193ce..d1b4668d2c46 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/arrow/issue_2136_2/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/arrow/issue_2136_2/output.js
@@ -1,4 +1,4 @@
-function f(x) {
-    console.log(x);
+function f() {
+    console.log(2);
 }
-f(2);
+f();
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/drop_unused/issue_2136_2/output.js b/crates/swc_ecma_minifier/tests/terser/compress/drop_unused/issue_2136_2/output.js
index 3bae317193ce..d1b4668d2c46 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/drop_unused/issue_2136_2/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/drop_unused/issue_2136_2/output.js
@@ -1,4 +1,4 @@
-function f(x) {
-    console.log(x);
+function f() {
+    console.log(2);
 }
-f(2);
+f();
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2601_1/output.js b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2601_1/output.js
index 9e44326bad4f..eca3efbf3b39 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2601_1/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2601_1/output.js
@@ -1,2 +1,5 @@
 var a = "FAIL";
-console.log(a = "PASS");
+(function() {
+    let b;
+    b && b(), a = "PASS";
+})(), console.log(a);
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_2/output.js b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_2/output.js
index 17d695e0edd6..a71a8976afba 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_2/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_2/output.js
@@ -1,2 +1,4 @@
 var c = "FAIL";
-(c = "PASS"), console.log(c);
+(function() {
+    c = "PASS";
+})(), console.log(c);
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_4/output.js b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_4/output.js
index 8bcd28693e3e..78916c4f4f21 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_4/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/functions/issue_2620_4/output.js
@@ -1,9 +1,10 @@
 var c = "FAIL";
 (function() {
     var a = 0 / 0;
+    let NaN;
     switch(a){
         case a:
-        case void (c = "PASS"):
+        case c = "PASS", NaN:
     }
 })();
 console.log(c);
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_else/output.js b/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_else/output.js
index 0e50dcd5829d..024738ae7c1b 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_else/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_else/output.js
@@ -1,6 +1,6 @@
-function f(x) {
+function f() {
     (function() {
-        x || console.log("PASS");
+        console.log("PASS");
     })();
 }
-f(0);
+f();
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_label/output.js b/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_label/output.js
index 719890b97acb..dfe4fd37b8e1 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_label/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/issue_1673/side_effects_label/output.js
@@ -1,9 +1,9 @@
-function f(x) {
-    (function () {
+function f() {
+    (function() {
         L: {
             console.log("PASS");
             break L;
         }
     })();
 }
-f(0);
+f();
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/issue_281/modified/output.js b/crates/swc_ecma_minifier/tests/terser/compress/issue_281/modified/output.js
index b7d0ff08bd6d..9527981bd7c5 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/issue_281/modified/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/issue_281/modified/output.js
@@ -1,5 +1,5 @@
-function f5(b) {
-    var a = b;
-    return b++ + a;
+function f5() {
+    let b = 1;
+    return b++ + 1;
 }
-console.log(f5(1));
+console.log(f5());
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_1/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_1/output.js
index 79cb7c0da8a3..0ee186d161a3 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_1/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_1/output.js
@@ -1,7 +1,7 @@
 function f() {
-    return function(b) {
+    return function() {
         return 2;
-    }(0) + function h() {
+    }(2) + function h() {
         return h();
     }();
 }
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_2/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_2/output.js
index 79cb7c0da8a3..0ee186d161a3 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_2/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/defun_inline_2/output.js
@@ -1,7 +1,7 @@
 function f() {
-    return function(b) {
+    return function() {
         return 2;
-    }(0) + function h() {
+    }(2) + function h() {
         return h();
     }();
 }
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/do_while/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/do_while/output.js
index f0842895c1a9..ac2b9dd3d85d 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/do_while/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/do_while/output.js
@@ -1,9 +1,10 @@
-function f(a) {
+function f() {
+    let a = 1;
     do (function() {
         a && (c = "PASS");
     })();
     while (a = 0)
 }
 var c = "FAIL";
-f(1);
+f();
 console.log(c);
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_conditional/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_conditional/output.js
index 3fab22ec4f19..2e23eb40eee2 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_conditional/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_conditional/output.js
@@ -1,9 +1,8 @@
-function baz(s) {
-    return s ? foo : bar;
+function baz() {
+    return bar;
 }
-function foo() {}
 function bar() {}
-(function () {
+(function() {
     var thing = baz();
     if (thing !== (thing = baz())) console.log("FAIL");
     else console.log("PASS");
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_local_conditional/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_local_conditional/output.js
index adfbe1e64544..1270eecacde9 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_local_conditional/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_local_conditional/output.js
@@ -1,7 +1,7 @@
-function baz(s) {
-    return s ? function () {} : function () {};
+function baz() {
+    return function() {};
 }
-(function () {
+(function() {
     var thing = baz();
     if (thing !== (thing = baz())) console.log("PASS");
     else console.log("FAIL");
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_yield/output.js b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_yield/output.js
index f11b4f033029..d8514ae2af02 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_yield/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/reduce_vars/escape_yield/output.js
@@ -1,5 +1,5 @@
 function foo() {}
-var gen = function*(s) {
+var gen = function*() {
     for(;;)yield foo;
 }();
 (function() {
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/switch/if_else8/output.js b/crates/swc_ecma_minifier/tests/terser/compress/switch/if_else8/output.js
index 4a0cfa4e3318..c238618bfd88 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/switch/if_else8/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/switch/if_else8/output.js
@@ -1,4 +1,4 @@
-function test(foo) {
-    return "bar" === foo ? "PASS" : "FAIL";
+function test() {
+    return "PASS";
 }
-console.log(test("bar"));
+console.log(test());
diff --git a/crates/swc_ecma_minifier/tests/terser/compress/typeof/duplicate_defun_arg_name/output.js b/crates/swc_ecma_minifier/tests/terser/compress/typeof/duplicate_defun_arg_name/output.js
index 4fa10c33dd0b..db4e33ad9068 100644
--- a/crates/swc_ecma_minifier/tests/terser/compress/typeof/duplicate_defun_arg_name/output.js
+++ b/crates/swc_ecma_minifier/tests/terser/compress/typeof/duplicate_defun_arg_name/output.js
@@ -1,4 +1,5 @@
-function long_name(long_name) {
-    return typeof long_name;
+function long_name() {
+    let long_name;
+    return "undefined";
 }
 console.log("function", long_name());
diff --git a/crates/swc_ecma_usage_analyzer/src/analyzer/mod.rs b/crates/swc_ecma_usage_analyzer/src/analyzer/mod.rs
index 4cee58545145..9df32f8e270a 100644
--- a/crates/swc_ecma_usage_analyzer/src/analyzer/mod.rs
+++ b/crates/swc_ecma_usage_analyzer/src/analyzer/mod.rs
@@ -435,6 +435,26 @@ where
                 self.data.var_or_default(i.to_id()).mark_used_as_callee();
             });
 
+            // Record call site arguments for parameter inlining optimization
+            if let Expr::Ident(callee_ident) = &**callee {
+                // Collect arguments for this call site
+                let mut call_args = Vec::new();
+                for arg in &n.args {
+                    if arg.spread.is_some() {
+                        // Spread arguments prevent parameter inlining
+                        call_args.clear();
+                        break;
+                    }
+                    call_args.push(Some(arg.expr.clone()));
+                }
+
+                // Only record if we have a valid argument list (no spread)
+                if !call_args.is_empty() || n.args.is_empty() {
+                    self.data
+                        .record_call_site_args(callee_ident.to_id(), &call_args);
+                }
+            }
+
             match &**callee {
                 Expr::Fn(callee) => {
                     for (idx, p) in callee.function.params.iter().enumerate() {
diff --git a/crates/swc_ecma_usage_analyzer/src/analyzer/storage.rs b/crates/swc_ecma_usage_analyzer/src/analyzer/storage.rs
index df2e9ee5f2b1..b1b59920b422 100644
--- a/crates/swc_ecma_usage_analyzer/src/analyzer/storage.rs
+++ b/crates/swc_ecma_usage_analyzer/src/analyzer/storage.rs
@@ -42,6 +42,10 @@ pub trait Storage: Sized + Default {
     fn mark_property_mutation(&mut self, id: Id);
 
     fn get_var_data(&self, id: Id) -> Option<&Self::VarData>;
+
+    /// Records arguments passed to a function at a call site.
+    /// Used for parameter inlining optimization.
+    fn record_call_site_args(&mut self, callee_id: Id, args: &[Option<Box<Expr>>]);
 }
 
 pub trait ScopeDataLike: Sized + Default + Clone {