tweak let_and_return diagnostic

clippy_lints/src/returns.rs

@@ -7,7 +7,7 @@ use syntax::source_map::Span;
 use syntax::visit::FnKind;
 use syntax_pos::BytePos;
 
-use crate::utils::{in_macro_or_desugar, match_path_ast, snippet_opt, span_lint_and_then, span_note_and_lint};
+use crate::utils::{in_macro_or_desugar, match_path_ast, snippet_opt, span_lint_and_then};
 
 declare_clippy_lint! {
  /// **What it does:** Checks for return statements at the end of a block.
@@ -164,13 +164,28 @@ impl Return {
  if match_path_ast(path, &[&*ident.name.as_str()]);
  if !in_external_macro(cx.sess(), initexpr.span);
  then {
- span_note_and_lint(cx,
- LET_AND_RETURN,
- retexpr.span,
- "returning the result of a let binding from a block. \
- Consider returning the expression directly.",
- initexpr.span,
- "this expression can be directly returned");
+ span_lint_and_then(
+ cx,
+ LET_AND_RETURN,
+ retexpr.span,
+ "returning the result of a let binding from a block",
+ |err| {
+ err.span_label(local.span, "unnecessary let binding");
+
+ if let Some(snippet) = snippet_opt(cx, initexpr.span) {
+ err.multipart_suggestion(
+ "return the expression directly",
+ vec![
+ (local.span, String::new()),
+ (retexpr.span, snippet),
+ ],
+ Applicability::MachineApplicable,
+ );
+ } else {
+ err.span_help(initexpr.span, "this expression can be directly returned");
+ }
+ },
+ );
  }
  }
  }

tests/ui/author/matches.stderr

@@ -1,15 +1,17 @@
-error: returning the result of a let binding from a block. Consider returning the expression directly.
+error: returning the result of a let binding from a block
  --> $DIR/matches.rs:9:13
  |
+LL | let x = 3;
+ | ---------- unnecessary let binding
 LL | x
  | ^
  |
  = note: `-D clippy::let-and-return` implied by `-D warnings`
-note: this expression can be directly returned
- --> $DIR/matches.rs:8:21
+help: return the expression directly
+ |
+LL | 
+LL | 3
  |
-LL | let x = 3;
- | ^
 
 error: aborting due to previous error
 

tests/ui/let_return.stderr

@@ -1,27 +1,30 @@
-error: returning the result of a let binding from a block. Consider returning the expression directly.
+error: returning the result of a let binding from a block
  --> $DIR/let_return.rs:7:5
  |
+LL | let x = 5;
+ | ---------- unnecessary let binding
 LL | x
  | ^
  |
  = note: `-D clippy::let-and-return` implied by `-D warnings`
-note: this expression can be directly returned
- --> $DIR/let_return.rs:6:13
+help: return the expression directly
+ |
+LL | 
+LL | 5
  |
-LL | let x = 5;
- | ^
 
-error: returning the result of a let binding from a block. Consider returning the expression directly.
+error: returning the result of a let binding from a block
  --> $DIR/let_return.rs:13:9
  |
+LL | let x = 5;
+ | ---------- unnecessary let binding
 LL | x
  | ^
+help: return the expression directly
  |
-note: this expression can be directly returned
- --> $DIR/let_return.rs:12:17
+LL | 
+LL | 5
  |
-LL | let x = 5;
- | ^
 
 error: aborting due to 2 previous errors