Trim whitespace in RemoveLet primary span

Separate `RemoveLet` span into primary span for `let` and removal
suggestion span for `let `, so that primary span does not include
whitespace.

Fixes: #133031

Signed-off-by: Tyrone Wu <[email protected]>

Author: tyrone-wu

Diff for: compiler/rustc_parse/src/errors.rs

@@ -650,8 +650,9 @@ pub(crate) struct LeftArrowOperator {
 #[diag(parse_remove_let)]
 pub(crate) struct RemoveLet {
     #[primary_span]
-    #[suggestion(applicability = "machine-applicable", code = "", style = "verbose")]
     pub span: Span,
+    #[suggestion(applicability = "machine-applicable", code = "", style = "verbose")]
+    pub suggestion: Span,
 }
 
 #[derive(Diagnostic)]

Diff for: compiler/rustc_parse/src/parser/pat.rs

@@ -685,7 +685,7 @@ impl<'a> Parser<'a> {
             self.bump();
             // Trim extra space after the `let`
             let span = lo.with_hi(self.token.span.lo());
-            self.dcx().emit_err(RemoveLet { span });
+            self.dcx().emit_err(RemoveLet { span: lo, suggestion: span });
             lo = self.token.span;
         }
 

Diff for: tests/ui/parser/unnecessary-let.stderr

@@ -2,7 +2,7 @@ error: expected pattern, found `let`
   --> $DIR/unnecessary-let.rs:2:9
    |
 LL |     for let x of [1, 2, 3] {}
-   |         ^^^^
+   |         ^^^
    |
 help: remove the unnecessary `let` keyword
    |
@@ -25,7 +25,7 @@ error: expected pattern, found `let`
   --> $DIR/unnecessary-let.rs:7:9
    |
 LL |         let 1 => {}
-   |         ^^^^
+   |         ^^^
    |
 help: remove the unnecessary `let` keyword
    |