feat(zero_repeat_side_effects): put the suggestion on two lines

Author: ada4a

clippy_lints/src/zero_repeat_side_effects.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher::VecArgs;
-use clippy_utils::source::snippet;
+use clippy_utils::source::{snippet, snippet_indent};
 use rustc_ast::LitKind;
 use rustc_data_structures::packed::Pu128;
 use rustc_errors::Applicability;
@@ -75,24 +75,34 @@ fn inner_check(cx: &LateContext<'_>, expr: &'_ rustc_hir::Expr<'_>, inner_expr:
         let return_type = cx.typeck_results().expr_ty(expr);
 
         let inner_expr = snippet(cx, inner_expr.span.source_callsite(), "..");
+        let indent = snippet_indent(cx, expr.span).unwrap_or_default();
         let vec = if is_vec { "vec!" } else { "" };
 
         let (span, sugg) = match parent_hir_node {
             Node::LetStmt(l) => (
                 l.span,
                 format!(
-                    "{inner_expr}; let {var_name}: {return_type} = {vec}[];",
+                    "{inner_expr};\n{indent}let {var_name}: {return_type} = {vec}[];",
                     var_name = snippet(cx, l.pat.span.source_callsite(), "..")
                 ),
             ),
             Node::Expr(x) if let ExprKind::Assign(l, _, _) = x.kind => (
                 x.span,
                 format!(
-                    "{inner_expr}; {var_name} = {vec}[] as {return_type}",
+                    "{inner_expr};\n{indent}{var_name} = {vec}[] as {return_type}",
                     var_name = snippet(cx, l.span.source_callsite(), "..")
                 ),
             ),
-            _ => (expr.span, format!("{{ {inner_expr}; {vec}[] as {return_type} }}")),
+            _ => (
+                expr.span,
+                format!(
+                    "\
+{{
+{indent}    {inner_expr};
+{indent}    {vec}[] as {return_type}
+{indent}}}"
+                ),
+            ),
         };
         span_lint_and_then(
             cx,

tests/ui/zero_repeat_side_effects.fixed

@@ -13,36 +13,51 @@ fn main() {
     // should trigger
 
     // on arrays
-    f(); let a: [i32; 0] = [];
+    f();
+    let a: [i32; 0] = [];
     //~^ zero_repeat_side_effects
     let mut b;
-    f(); b = [] as [i32; 0];
+    f();
+    b = [] as [i32; 0];
     //~^ zero_repeat_side_effects
 
     // on vecs
     // vecs dont support inferring value of consts
-    f(); let c: std::vec::Vec<i32> = vec![];
+    f();
+    let c: std::vec::Vec<i32> = vec![];
     //~^ zero_repeat_side_effects
     let d;
-    f(); d = vec![] as std::vec::Vec<i32>;
+    f();
+    d = vec![] as std::vec::Vec<i32>;
     //~^ zero_repeat_side_effects
 
     // for macros
-    println!("side effect"); let e: [(); 0] = [];
+    println!("side effect");
+    let e: [(); 0] = [];
     //~^ zero_repeat_side_effects
 
     // for nested calls
-    { f() }; let g: [i32; 0] = [];
+    { f() };
+    let g: [i32; 0] = [];
     //~^ zero_repeat_side_effects
 
     // as function param
-    drop({ f(); vec![] as std::vec::Vec<i32> });
+    drop({
+        f();
+        vec![] as std::vec::Vec<i32>
+    });
     //~^ zero_repeat_side_effects
 
     // when singled out/not part of assignment/local
-    { f(); vec![] as std::vec::Vec<i32> };
+    {
+        f();
+        vec![] as std::vec::Vec<i32>
+    };
     //~^ zero_repeat_side_effects
-    { f(); [] as [i32; 0] };
+    {
+        f();
+        [] as [i32; 0]
+    };
     //~^ zero_repeat_side_effects
 
     // should not trigger
@@ -96,8 +111,14 @@ fn issue_14681() {
 
     foo(&[Some(0i64); 0]);
     foo(&[Some(Some(0i64)); 0]);
-    foo(&{ Some(f()); [] as [std::option::Option<i32>; 0] });
+    foo(&{
+        Some(f());
+        [] as [std::option::Option<i32>; 0]
+    });
     //~^ zero_repeat_side_effects
-    foo(&{ Some(Some(S::new())); [] as [std::option::Option<std::option::Option<S>>; 0] });
+    foo(&{
+        Some(Some(S::new()));
+        [] as [std::option::Option<std::option::Option<S>>; 0]
+    });
     //~^ zero_repeat_side_effects
 }

tests/ui/zero_repeat_side_effects.stderr

@@ -8,8 +8,8 @@ LL |     let a = [f(); 0];
    = help: to override `-D warnings` add `#[allow(clippy::zero_repeat_side_effects)]`
 help: consider performing the side effect separately
    |
-LL -     let a = [f(); 0];
-LL +     f(); let a: [i32; 0] = [];
+LL ~     f();
+LL +     let a: [i32; 0] = [];
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -20,8 +20,8 @@ LL |     b = [f(); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     b = [f(); 0];
-LL +     f(); b = [] as [i32; 0];
+LL ~     f();
+LL ~     b = [] as [i32; 0];
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -32,8 +32,8 @@ LL |     let c = vec![f(); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     let c = vec![f(); 0];
-LL +     f(); let c: std::vec::Vec<i32> = vec![];
+LL ~     f();
+LL +     let c: std::vec::Vec<i32> = vec![];
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -44,8 +44,8 @@ LL |     d = vec![f(); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     d = vec![f(); 0];
-LL +     f(); d = vec![] as std::vec::Vec<i32>;
+LL ~     f();
+LL ~     d = vec![] as std::vec::Vec<i32>;
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -56,8 +56,8 @@ LL |     let e = [println!("side effect"); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     let e = [println!("side effect"); 0];
-LL +     println!("side effect"); let e: [(); 0] = [];
+LL ~     println!("side effect");
+LL +     let e: [(); 0] = [];
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -68,8 +68,8 @@ LL |     let g = [{ f() }; 0];
    |
 help: consider performing the side effect separately
    |
-LL -     let g = [{ f() }; 0];
-LL +     { f() }; let g: [i32; 0] = [];
+LL ~     { f() };
+LL +     let g: [i32; 0] = [];
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -80,8 +80,10 @@ LL |     drop(vec![f(); 0]);
    |
 help: consider performing the side effect separately
    |
-LL -     drop(vec![f(); 0]);
-LL +     drop({ f(); vec![] as std::vec::Vec<i32> });
+LL ~     drop({
+LL +         f();
+LL +         vec![] as std::vec::Vec<i32>
+LL ~     });
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -92,8 +94,10 @@ LL |     vec![f(); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     vec![f(); 0];
-LL +     { f(); vec![] as std::vec::Vec<i32> };
+LL ~     {
+LL +         f();
+LL +         vec![] as std::vec::Vec<i32>
+LL ~     };
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -104,8 +108,10 @@ LL |     [f(); 0];
    |
 help: consider performing the side effect separately
    |
-LL -     [f(); 0];
-LL +     { f(); [] as [i32; 0] };
+LL ~     {
+LL +         f();
+LL +         [] as [i32; 0]
+LL ~     };
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -116,8 +122,10 @@ LL |     foo(&[Some(f()); 0]);
    |
 help: consider performing the side effect separately
    |
-LL -     foo(&[Some(f()); 0]);
-LL +     foo(&{ Some(f()); [] as [std::option::Option<i32>; 0] });
+LL ~     foo(&{
+LL +         Some(f());
+LL +         [] as [std::option::Option<i32>; 0]
+LL ~     });
    |
 
 error: expression with side effects as the initial value in a zero-sized array initializer
@@ -128,8 +136,10 @@ LL |     foo(&[Some(Some(S::new())); 0]);
    |
 help: consider performing the side effect separately
    |
-LL -     foo(&[Some(Some(S::new())); 0]);
-LL +     foo(&{ Some(Some(S::new())); [] as [std::option::Option<std::option::Option<S>>; 0] });
+LL ~     foo(&{
+LL +         Some(Some(S::new()));
+LL +         [] as [std::option::Option<std::option::Option<S>>; 0]
+LL ~     });
    |
 
 error: aborting due to 11 previous errors