Use smaller span for suggestions

compiler/rustc_attr/src/session_diagnostics.rs

@@ -223,14 +223,12 @@ impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
             error_code!(E0565),
         );
         if self.is_bytestr {
-            if let Ok(lint_str) = sess.source_map().span_to_snippet(self.span) {
-                diag.span_suggestion(
-                    self.span,
-                    fluent::attr::unsupported_literal_suggestion,
-                    &lint_str[1..],
-                    Applicability::MaybeIncorrect,
-                );
-            }
+            diag.span_suggestion(
+                sess.source_map().start_point(self.span),
+                fluent::attr::unsupported_literal_suggestion,
+                "",
+                Applicability::MaybeIncorrect,
+            );
         }
         diag
     }

compiler/rustc_typeck/src/check/method/suggest.rs

@@ -1299,7 +1299,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // local binding
                     if let hir::def::Res::Local(hir_id) = path.res {
                         let span = tcx.hir().span(hir_id);
-                        let snippet = tcx.sess.source_map().span_to_snippet(span);
                         let filename = tcx.sess.source_map().span_to_filename(span);
 
                         let parent_node =
@@ -1309,22 +1308,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             concrete_type,
                         );
 
-                        match (filename, parent_node, snippet) {
+                        match (filename, parent_node) {
                             (
                                 FileName::Real(_),
                                 Node::Local(hir::Local {
                                     source: hir::LocalSource::Normal,
                                     ty,
                                     ..
                                 }),
-                                Ok(ref snippet),
                             ) => {
+                                let type_span = ty.map(|ty| ty.span.with_lo(span.hi())).unwrap_or(span.shrink_to_hi());
                                 err.span_suggestion(
                                     // account for `let x: _ = 42;`
-                                    //                  ^^^^
-                                    span.to(ty.as_ref().map(|ty| ty.span).unwrap_or(span)),
+                                    //                   ^^^
+                                    type_span,
                                     &msg,
-                                    format!("{}: {}", snippet, concrete_type),
+                                    format!(": {concrete_type}"),
                                     Applicability::MaybeIncorrect,
                                 );
                             }

compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs

@@ -763,16 +763,13 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
         // If there is a single unbound associated type and a single excess generic param
         // suggest replacing the generic param with the associated type bound
         if provided_args_matches_unbound_traits && !unbound_types.is_empty() {
-            let mut suggestions = vec![];
             let unused_generics = &self.gen_args.args[self.num_expected_type_or_const_args()..];
-            for (potential, name) in iter::zip(unused_generics, &unbound_types) {
-                if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(potential.span()) {
-                    suggestions.push((potential.span(), format!("{} = {}", name, snippet)));
-                }
-            }
+            let suggestions = iter::zip(unused_generics, &unbound_types)
+                .map(|(potential, name)| (potential.span().shrink_to_lo(), format!("{name} = ")))
+                .collect::<Vec<_>>();
 
             if !suggestions.is_empty() {
-                err.multipart_suggestion(
+                err.multipart_suggestion_verbose(
                     &format!(
                         "replace the generic bound{s} with the associated type{s}",
                         s = pluralize!(unbound_types.len())

src/test/ui/conditional-compilation/cfg-attr-syntax-validation.stderr

@@ -50,7 +50,9 @@ error[E0565]: literal in `cfg` predicate value must be a string
   --> $DIR/cfg-attr-syntax-validation.rs:25:11
    |
 LL | #[cfg(a = b"hi")]
-   |           ^^^^^ help: consider removing the prefix: `"hi"`
+   |           -^^^^
+   |           |
+   |           help: consider removing the prefix
 
 error: expected unsuffixed literal or identifier, found `concat!("nonexistent")`
   --> $DIR/cfg-attr-syntax-validation.rs:30:25

src/test/ui/const-generics/issues/issue-87493.stderr

@@ -13,15 +13,17 @@ error[E0107]: this trait takes 0 generic arguments but 1 generic argument was su
   --> $DIR/issue-87493.rs:8:8
    |
 LL |     T: MyTrait<Assoc == S::Assoc>,
-   |        ^^^^^^^ ----------------- help: replace the generic bound with the associated type: `Assoc = Assoc == S::Assoc`
-   |        |
-   |        expected 0 generic arguments
+   |        ^^^^^^^ expected 0 generic arguments
    |
 note: trait defined here, with 0 generic parameters
   --> $DIR/issue-87493.rs:1:11
    |
 LL | pub trait MyTrait {
    |           ^^^^^^^
+help: replace the generic bound with the associated type
+   |
+LL |     T: MyTrait<Assoc = Assoc == S::Assoc>,
+   |                +++++++
 
 error: aborting due to 2 previous errors
 

src/test/ui/deprecation/deprecation-sanity.stderr

@@ -44,7 +44,9 @@ error[E0565]: literal in `deprecated` value must be a string
   --> $DIR/deprecation-sanity.rs:19:25
    |
 LL |     #[deprecated(note = b"test")]
-   |                         ^^^^^^^ help: consider removing the prefix: `"test"`
+   |                         -^^^^^^
+   |                         |
+   |                         help: consider removing the prefix
 
 error[E0565]: item in `deprecated` must be a key/value pair
   --> $DIR/deprecation-sanity.rs:22:18

src/test/ui/error-codes/E0107.stderr

@@ -142,7 +142,7 @@ LL | pub trait T {
 help: replace the generic bounds with the associated types
    |
 LL | fn trait_bound_generic<I: T<A = u8, B = u16>>(_i: I) {
-   |                             ~~~~~~  ~~~~~~~
+   |                             +++     +++
 
 error: aborting due to 10 previous errors
 

src/test/ui/error-codes/E0565-2.stderr

@@ -2,7 +2,9 @@ error[E0565]: literal in `deprecated` value must be a string
   --> $DIR/E0565-2.rs:2:22
    |
 LL | #[deprecated(since = b"1.29", note = "hi")]
-   |                      ^^^^^^^ help: consider removing the prefix: `"1.29"`
+   |                      -^^^^^^
+   |                      |
+   |                      help: consider removing the prefix
 
 error: aborting due to previous error
 

src/test/ui/methods/method-on-ambiguous-numeric-type.stderr

@@ -18,7 +18,7 @@ LL |     let x = y.neg();
 help: you must specify a type for this binding, like `f32`
    |
 LL |     let y: f32 = 2.0;
-   |         ~~~~~~
+   |          +++++
 
 error[E0689]: can't call method `pow` on ambiguous numeric type `{integer}`
   --> $DIR/method-on-ambiguous-numeric-type.rs:19:26
@@ -37,7 +37,7 @@ LL |     local_bar.pow(2);
 help: you must specify a type for this binding, like `i32`
    |
 LL |     ($ident:ident) => { let $ident: i32 = 42; }
-   |                             ~~~~~~~~~~~
+   |                                   +++++
 
 error[E0689]: can't call method `pow` on ambiguous numeric type `{integer}`
   --> $DIR/method-on-ambiguous-numeric-type.rs:30:9
@@ -46,10 +46,10 @@ LL |     bar.pow(2);
    |         ^^^
    |
 help: you must specify a type for this binding, like `i32`
-  --> $DIR/auxiliary/macro-in-other-crate.rs:3:29
+  --> $DIR/auxiliary/macro-in-other-crate.rs:3:35
    |
 LL |     ($ident:ident) => { let $ident: i32 = 42; }
-   |                             ~~~~~~~~~~~
+   |                                   +++++
 
 error: aborting due to 5 previous errors
 

src/test/ui/suggestions/use-type-argument-instead-of-assoc-type.stderr

@@ -12,7 +12,7 @@ LL | pub trait T<X, Y> {
 help: replace the generic bounds with the associated types
    |
 LL |     i: Box<dyn T<usize, usize, A = usize, C = usize, B=usize>>,
-   |                                ~~~~~~~~~  ~~~~~~~~~
+   |                                +++        +++
 
 error[E0191]: the value of the associated types `A` (from trait `T`), `C` (from trait `T`) must be specified
   --> $DIR/use-type-argument-instead-of-assoc-type.rs:7:16