Auto merge of #52450 - PramodBisht:issue/52413, r=estebank

Closes #52413: Provide structured suggestion instead of label

Provide structured suggestion instead of label
r? @estebank

Author: bors

src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -65,9 +65,10 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             region_info
         );
 
-        let (arg, new_ty, br, is_first, scope_def_id, is_impl_item) = (
+        let (arg, new_ty, new_ty_span, br, is_first, scope_def_id, is_impl_item) = (
             anon_arg_info.arg,
             anon_arg_info.arg_ty,
+            anon_arg_info.arg_ty_span,
             anon_arg_info.bound_region,
             anon_arg_info.is_first,
             region_info.def_id,
@@ -110,9 +111,10 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             E0621,
             "explicit lifetime required in {}",
             error_var
-        ).span_label(
-            arg.pat.span,
-            format!("consider changing {} to `{}`", span_label_var, new_ty),
+        ).span_suggestion(
+            new_ty_span,
+            &format!("add explicit lifetime `{}` to {}", named, span_label_var),
+            new_ty.to_string()
         )
             .span_label(span, format!("lifetime `{}` required", named))
             .emit();

src/librustc/infer/error_reporting/nice_region_error/util.rs

@@ -27,6 +27,8 @@ pub(super) struct AnonymousArgInfo<'tcx> {
     pub arg_ty: Ty<'tcx>,
     // the ty::BoundRegion corresponding to the anonymous region
     pub bound_region: ty::BoundRegion,
+    // arg_ty_span contains span of argument type
+    pub arg_ty_span : Span,
     // corresponds to id the argument is the first parameter
     // in the declaration
     pub is_first: bool,
@@ -74,12 +76,16 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         if let Some(node_id) = hir.as_local_node_id(id) {
             if let Some(body_id) = hir.maybe_body_owned_by(node_id) {
                 let body = hir.body(body_id);
+                let owner_id = hir.body_owner(body_id);
+                let fn_decl = hir.fn_decl(owner_id).unwrap();
                 if let Some(tables) = self.tables {
                     body.arguments
                         .iter()
                         .enumerate()
                         .filter_map(|(index, arg)| {
                             // May return None; sometimes the tables are not yet populated.
+                            let ty_hir_id = fn_decl.inputs[index].hir_id;
+                            let arg_ty_span = hir.span(hir.hir_to_node_id(ty_hir_id));
                             let ty = tables.node_id_to_type_opt(arg.hir_id)?;
                             let mut found_anon_region = false;
                             let new_arg_ty = self.tcx.fold_regions(&ty, &mut false, |r, _| {
@@ -95,6 +101,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                                 Some(AnonymousArgInfo {
                                     arg: arg,
                                     arg_ty: new_arg_ty,
+                                    arg_ty_span : arg_ty_span,
                                     bound_region: bound_region,
                                     is_first: is_first,
                                 })

src/test/ui/in-band-lifetimes/mismatched.nll.stderr

@@ -14,9 +14,9 @@ error[E0621]: explicit lifetime required in the type of `y`
   --> $DIR/mismatched.rs:14:42
    |
 LL | fn foo(x: &'a u32, y: &u32) -> &'a u32 { y } //~ ERROR explicit lifetime required
-   |                    -                     ^ lifetime `'a` required
-   |                    |
-   |                    consider changing the type of `y` to `&'a u32`
+   |                       ----               ^ lifetime `'a` required
+   |                       |
+   |                       help: add explicit lifetime `'a` to the type of `y`: `&'a u32`
 
 error: unsatisfied lifetime constraints
   --> $DIR/mismatched.rs:16:46

src/test/ui/in-band-lifetimes/mismatched.stderr

@@ -2,9 +2,9 @@ error[E0621]: explicit lifetime required in the type of `y`
   --> $DIR/mismatched.rs:14:42
    |
 LL | fn foo(x: &'a u32, y: &u32) -> &'a u32 { y } //~ ERROR explicit lifetime required
-   |                    -                     ^ lifetime `'a` required
-   |                    |
-   |                    consider changing the type of `y` to `&'a u32`
+   |                       ----               ^ lifetime `'a` required
+   |                       |
+   |                       help: add explicit lifetime `'a` to the type of `y`: `&'a u32`
 
 error[E0623]: lifetime mismatch
   --> $DIR/mismatched.rs:16:46

src/test/ui/in-band-lifetimes/mismatched_trait.nll.stderr

@@ -8,7 +8,7 @@ error[E0621]: explicit lifetime required in the type of `y`
   --> $DIR/mismatched_trait.rs:16:9
    |
 LL |     fn baz(&self, x: &'a u32, y: &u32) -> &'a u32 {
-   |                               - consider changing the type of `y` to `&'a u32`
+   |                                  ---- help: add explicit lifetime `'a` to the type of `y`: `&'a u32`
 LL |         y //~ ERROR explicit lifetime required
    |         ^ lifetime `'a` required
 

src/test/ui/in-band-lifetimes/mismatched_trait.stderr

@@ -2,7 +2,7 @@ error[E0621]: explicit lifetime required in the type of `y`
   --> $DIR/mismatched_trait.rs:16:9
    |
 LL |     fn baz(&self, x: &'a u32, y: &u32) -> &'a u32 {
-   |                               - consider changing the type of `y` to `&'a u32`
+   |                                  ---- help: add explicit lifetime `'a` to the type of `y`: `&'a u32`
 LL |         y //~ ERROR explicit lifetime required
    |         ^ lifetime `'a` required
 

src/test/ui/issue-13058.stderr

@@ -2,7 +2,7 @@ error[E0621]: explicit lifetime required in the type of `cont`
   --> $DIR/issue-13058.rs:24:26
    |
 LL | fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
-   |                                                               ---- consider changing the type of `cont` to `&'r T`
+   |                                                                     -- help: add explicit lifetime `'r` to the type of `cont`: `&'r T`
 LL | {
 LL |     let cont_iter = cont.iter();
    |                          ^^^^ lifetime `'r` required

src/test/ui/issue-14285.nll.stderr

@@ -8,7 +8,7 @@ error[E0621]: explicit lifetime required in the type of `a`
   --> $DIR/issue-14285.rs:22:7
    |
 LL | fn foo<'a>(a: &Foo) -> B<'a> {
-   |            - consider changing the type of `a` to `&'a (dyn Foo + 'a)`
+   |               ---- help: add explicit lifetime `'a` to the type of `a`: `&'a (dyn Foo + 'a)`
 LL |     B(a)    //~ ERROR 22:5: 22:9: explicit lifetime required in the type of `a` [E0621]
    |       ^ lifetime `'a` required
 

src/test/ui/issue-14285.stderr

@@ -2,7 +2,7 @@ error[E0621]: explicit lifetime required in the type of `a`
   --> $DIR/issue-14285.rs:22:5
    |
 LL | fn foo<'a>(a: &Foo) -> B<'a> {
-   |            - consider changing the type of `a` to `&'a (dyn Foo + 'a)`
+   |               ---- help: add explicit lifetime `'a` to the type of `a`: `&'a (dyn Foo + 'a)`
 LL |     B(a)    //~ ERROR 22:5: 22:9: explicit lifetime required in the type of `a` [E0621]
    |     ^^^^ lifetime `'a` required
 

src/test/ui/issue-15034.nll.stderr

@@ -8,7 +8,7 @@ error[E0621]: explicit lifetime required in the type of `lexer`
   --> $DIR/issue-15034.rs:27:25
    |
 LL |     pub fn new(lexer: &'a mut Lexer) -> Parser<'a> {
-   |                ----- consider changing the type of `lexer` to `&'a mut Lexer<'a>`
+   |                       ------------- help: add explicit lifetime `'a` to the type of `lexer`: `&'a mut Lexer<'a>`
 LL |         Parser { lexer: lexer }
    |                         ^^^^^ lifetime `'a` required