feat(lint): emit suggestions for named_struct_fields lint (#11982)

* feat(lint): enhance named struct fields lint with suggestions for auto-fix

- Updated the `NamedStructFields` lint to emit suggestions for initializing structs with named fields.
- Updated test data to reflect the new suggestion format in lint messages.

* fix: warn without suggestion if missing struct/arg name

* fix: field_name

Co-authored-by: onbjerg <[email protected]>

* fix: previous suggestion, arg/field swap

- fmt
- fix missing ')'

---------

Co-authored-by: onbjerg <[email protected]>

Author: mablr

crates/lint/src/sol/info/named_struct_fields.rs

@@ -1,7 +1,7 @@
 use solar::sema::hir::{CallArgs, CallArgsKind, Expr, ExprKind, ItemId, Res};
 
 use crate::{
-    linter::{LateLintPass, LintContext},
+    linter::{LateLintPass, LintContext, Suggestion},
     sol::{Severity, SolLint, info::NamedStructFields},
 };
 
@@ -16,16 +16,59 @@ impl<'hir> LateLintPass<'hir> for NamedStructFields {
     fn check_expr(
         &mut self,
         ctx: &LintContext,
-        _hir: &'hir solar::sema::hir::Hir<'hir>,
+        hir: &'hir solar::sema::hir::Hir<'hir>,
         expr: &'hir solar::sema::hir::Expr<'hir>,
     ) {
-        if let ExprKind::Call(
-            Expr { kind: ExprKind::Ident([Res::Item(ItemId::Struct(_struct_id))]), .. },
-            CallArgs { kind: CallArgsKind::Unnamed(_args), .. },
+        let ExprKind::Call(
+            Expr { kind: ExprKind::Ident([Res::Item(ItemId::Struct(struct_id))]), span, .. },
+            CallArgs { kind: CallArgsKind::Unnamed(args), .. },
             _,
         ) = &expr.kind
-        {
+        else {
+            return;
+        };
+
+        let strukt = hir.strukt(*struct_id);
+        let fields = &strukt.fields;
+
+        // Basic sanity conditions for a consistent auto-fix
+        if fields.len() != args.len() || fields.is_empty() {
+            // Emit without suggestion
             ctx.emit(&NAMED_STRUCT_FIELDS, expr.span);
+            return;
         }
+
+        // Get struct name snippet and emit without suggestion if we can't get it
+        let Some(struct_name_snippet) = ctx.span_to_snippet(*span) else {
+            // Emit without suggestion if we can't get the struct name snippet
+            ctx.emit(&NAMED_STRUCT_FIELDS, expr.span);
+            return;
+        };
+
+        // Collect field names and corresponding argument source snippets
+        let mut field_assignments = Vec::new();
+        for (field_id, arg) in fields.iter().zip(args.iter()) {
+            let field = hir.variable(*field_id);
+
+            let Some((arg_snippet, field_name)) =
+                ctx.span_to_snippet(arg.span).zip(field.name.map(|n| n.to_string()))
+            else {
+                // Emit without suggestion if we can't get argument snippet
+                ctx.emit(&NAMED_STRUCT_FIELDS, expr.span);
+                return;
+            };
+
+            field_assignments.push(format!("{field_name}: {arg_snippet}"));
+        }
+
+        ctx.emit_with_suggestion(
+            &NAMED_STRUCT_FIELDS,
+            expr.span,
+            Suggestion::fix(
+                format!("{}({{ {} }})", struct_name_snippet, field_assignments.join(", ")),
+                solar::interface::diagnostics::Applicability::MachineApplicable,
+            )
+            .with_desc("consider using named fields"),
+        );
     }
 }

crates/lint/testdata/NamedStructFields.stderr

@@ -2,7 +2,7 @@ note[named-struct-fields]: prefer initializing structs with named fields
   --> ROOT/testdata/NamedStructFields.sol:LL:CC
    |
 LL |         Person memory person = Person("Alice", 25, address(0));
-   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using named fields: `Person({ name: "Alice", age: 25, wallet: address(0) })`
    |
    = help: https://book.getfoundry.sh/reference/forge/forge-lint#named-struct-fields