Point to where missing return type should go

rust-lang · Oct 4, 2023 · 137b6d0 · 137b6d0
1 parent eea2614
commit 137b6d0
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Showing 34 changed files with 86 additions and 71 deletions.
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -1189,7 +1189,7 @@ fn report_trait_method_mismatch<'tcx>(
                     let ap = Applicability::MachineApplicable;
                     match sig.decl.output {
                         hir::FnRetTy::DefaultReturn(sp) => {
-                            let sugg = format!("-> {} ", trait_sig.output());
+                            let sugg = format!(" -> {}", trait_sig.output());
                             diag.span_suggestion_verbose(sp, msg, sugg, ap);
                         }
                         hir::FnRetTy::Return(hir_ty) => {

diff --git a/compiler/rustc_hir_typeck/src/errors.rs b/compiler/rustc_hir_typeck/src/errors.rs
@@ -110,7 +110,7 @@ pub struct AddressOfTemporaryTaken {
 pub enum AddReturnTypeSuggestion {
     #[suggestion(
         hir_typeck_add_return_type_add,
-        code = "-> {found} ",
+        code = " -> {found}",
         applicability = "machine-applicable"
     )]
     Add {
@@ -120,7 +120,7 @@ pub enum AddReturnTypeSuggestion {
     },
     #[suggestion(
         hir_typeck_add_return_type_missing_here,
-        code = "-> _ ",
+        code = " -> _",
         applicability = "has-placeholders"
     )]
     MissingHere {

diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -782,8 +782,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
             hir::FnRetTy::Return(hir_ty) => {
-                let span = hir_ty.span;
-
                 if let hir::TyKind::OpaqueDef(item_id, ..) = hir_ty.kind
                     && let hir::Node::Item(hir::Item {
                         kind: hir::ItemKind::OpaqueTy(op_ty),
@@ -799,28 +797,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     debug!(?found);
                     if found.is_suggestable(self.tcx, false) {
                         if term.span.is_empty() {
-                            err.subdiagnostic(errors::AddReturnTypeSuggestion::Add { span, found: found.to_string() });
+                            err.subdiagnostic(errors::AddReturnTypeSuggestion::Add { span: term.span, found: found.to_string() });
                             return true;
                         } else {
-                            err.subdiagnostic(errors::ExpectedReturnTypeLabel::Other { span, expected });
+                            err.subdiagnostic(errors::ExpectedReturnTypeLabel::Other { span: term.span, expected });
                         }
                     }
-                }
-
-                // Only point to return type if the expected type is the return type, as if they
-                // are not, the expectation must have been caused by something else.
-                debug!("return type {:?}", hir_ty);
-                let ty = self.astconv().ast_ty_to_ty(hir_ty);
-                debug!("return type {:?}", ty);
-                debug!("expected type {:?}", expected);
-                let bound_vars = self.tcx.late_bound_vars(hir_ty.hir_id.owner.into());
-                let ty = Binder::bind_with_vars(ty, bound_vars);
-                let ty = self.normalize(span, ty);
-                let ty = self.tcx.erase_late_bound_regions(ty);
-                if self.can_coerce(expected, ty) {
-                    err.subdiagnostic(errors::ExpectedReturnTypeLabel::Other { span, expected });
-                    self.try_suggest_return_impl_trait(err, expected, ty, fn_id);
-                    return true;
+                } else {
+                    // Only point to return type if the expected type is the return type, as if they
+                    // are not, the expectation must have been caused by something else.
+                    debug!("return type {:?}", hir_ty);
+                    let ty = self.astconv().ast_ty_to_ty(hir_ty);
+                    debug!("return type {:?}", ty);
+                    debug!("expected type {:?}", expected);
+                    let bound_vars = self.tcx.late_bound_vars(hir_ty.hir_id.owner.into());
+                    let ty = Binder::bind_with_vars(ty, bound_vars);
+                    let ty = self.normalize(hir_ty.span, ty);
+                    let ty = self.tcx.erase_late_bound_regions(ty);
+                    if self.can_coerce(expected, ty) {
+                        err.subdiagnostic(errors::ExpectedReturnTypeLabel::Other { span: hir_ty.span, expected });
+                        self.try_suggest_return_impl_trait(err, expected, ty, fn_id);
+                        return true;
+                    }
                 }
             }
             _ => {}

diff --git a/compiler/rustc_infer/src/errors/mod.rs b/compiler/rustc_infer/src/errors/mod.rs
@@ -194,13 +194,13 @@ impl<'a> SourceKindMultiSuggestion<'a> {
         data: &'a FnRetTy<'a>,
         should_wrap_expr: Option<Span>,
     ) -> Self {
-        let (arrow, post) = match data {
-            FnRetTy::DefaultReturn(_) => ("-> ", " "),
-            _ => ("", ""),
+        let arrow = match data {
+            FnRetTy::DefaultReturn(_) => " -> ",
+            _ => "",
         };
         let (start_span, start_span_code, end_span) = match should_wrap_expr {
-            Some(end_span) => (data.span(), format!("{arrow}{ty_info}{post}{{ "), Some(end_span)),
-            None => (data.span(), format!("{arrow}{ty_info}{post}"), None),
+            Some(end_span) => (data.span(), format!("{arrow}{ty_info} {{"), Some(end_span)),
+            None => (data.span(), format!("{arrow}{ty_info}"), None),
         };
         Self::ClosureReturn { start_span, start_span_code, end_span }
     }

diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
@@ -247,7 +247,7 @@ impl<'a> Parser<'a> {
             )?;
             FnRetTy::Ty(ty)
         } else {
-            FnRetTy::Default(self.token.span.shrink_to_lo())
+            FnRetTy::Default(self.prev_token.span.shrink_to_hi())
         })
     }
 

diff --git a/tests/ui/associated-type-bounds/issue-71443-1.stderr b/tests/ui/associated-type-bounds/issue-71443-1.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-71443-1.rs:6:5
    |
 LL | fn hello<F: for<'a> Iterator<Item: 'a>>() {
-   |                                           - help: try adding a return type: `-> Incorrect`
+   |                                          - help: try adding a return type: `-> Incorrect`
 LL |     Incorrect
    |     ^^^^^^^^^ expected `()`, found `Incorrect`
 

diff --git a/tests/ui/block-result/block-must-not-have-result-res.stderr b/tests/ui/block-result/block-must-not-have-result-res.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/block-must-not-have-result-res.rs:5:9
    |
 LL |     fn drop(&mut self) {
-   |                        - expected `()` because of default return type
+   |                       - expected `()` because of default return type
 LL |         true
    |         ^^^^ expected `()`, found `bool`
 

diff --git a/tests/ui/block-result/issue-20862.stderr b/tests/ui/block-result/issue-20862.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-20862.rs:2:5
    |
 LL | fn foo(x: i32) {
-   |                - help: a return type might be missing here: `-> _`
+   |               - help: a return type might be missing here: `-> _`
 LL |     |y| x + y
    |     ^^^^^^^^^ expected `()`, found closure
    |

diff --git a/tests/ui/block-result/issue-22645.stderr b/tests/ui/block-result/issue-22645.stderr
@@ -17,7 +17,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-22645.rs:15:3
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |   let b = Bob + 3.5;
 LL |   b + 3
    |   ^^^^^ expected `()`, found `Bob`

diff --git a/tests/ui/block-result/issue-5500.stderr b/tests/ui/block-result/issue-5500.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-5500.rs:2:5
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |     &panic!()
    |     ^^^^^^^^^ expected `()`, found `&_`
    |

diff --git a/tests/ui/closures/add_semicolon_non_block_closure.stderr b/tests/ui/closures/add_semicolon_non_block_closure.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/add_semicolon_non_block_closure.rs:8:12
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |     foo(|| bar())
    |            ^^^^^ expected `()`, found `i32`
    |

diff --git a/tests/ui/closures/binder/implicit-return.stderr b/tests/ui/closures/binder/implicit-return.stderr
@@ -1,8 +1,8 @@
 error: implicit types in closure signatures are forbidden when `for<...>` is present
-  --> $DIR/implicit-return.rs:4:34
+  --> $DIR/implicit-return.rs:4:33
    |
 LL |     let _f = for<'a> |_: &'a ()| {};
-   |              -------             ^
+   |              -------            ^
    |              |
    |              `for<...>` is here
 

diff --git a/tests/ui/closures/binder/implicit-stuff.stderr b/tests/ui/closures/binder/implicit-stuff.stderr
@@ -41,10 +41,10 @@ LL |     let _ = for<'a> |x: &'a ()| -> &() { x };
    |                                    ^ explicit lifetime name needed here
 
 error: implicit types in closure signatures are forbidden when `for<...>` is present
-  --> $DIR/implicit-stuff.rs:5:22
+  --> $DIR/implicit-stuff.rs:5:21
    |
 LL |     let _ = for<> || {};
-   |             -----    ^
+   |             -----   ^
    |             |
    |             `for<...>` is here
 

diff --git a/tests/ui/codemap_tests/tab.stderr b/tests/ui/codemap_tests/tab.stderr
@@ -8,7 +8,7 @@ error[E0308]: mismatched types
   --> $DIR/tab.rs:8:2
    |
 LL | fn foo() {
-   |          - help: try adding a return type: `-> &'static str`
+   |         - help: try adding a return type: `-> &'static str`
 LL |     "bar            boo"
    |     ^^^^^^^^^^^^^^^^^^^^ expected `()`, found `&str`
 

diff --git a/tests/ui/compare-method/bad-self-type.stderr b/tests/ui/compare-method/bad-self-type.stderr
@@ -28,10 +28,10 @@ LL |     fn foo(self);
               found signature `fn(Box<MyFuture>)`
 
 error[E0053]: method `bar` has an incompatible type for trait
-  --> $DIR/bad-self-type.rs:24:18
+  --> $DIR/bad-self-type.rs:24:17
    |
 LL |     fn bar(self) {}
-   |                  ^ expected `Option<()>`, found `()`
+   |                 ^ expected `Option<()>`, found `()`
    |
 note: type in trait
   --> $DIR/bad-self-type.rs:18:21

diff --git a/tests/ui/impl-trait/in-trait/refine.stderr b/tests/ui/impl-trait/in-trait/refine.stderr
@@ -30,8 +30,8 @@ LL |     fn bar() {}
    = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
 help: replace the return type so that it matches the trait
    |
-LL |     fn bar() -> impl Sized {}
-   |              +++++++++++++
+LL |     fn bar()-> impl Sized  {}
+   |             +++++++++++++
 
 error: impl trait in impl method signature does not match trait method signature
   --> $DIR/refine.rs:22:17

diff --git a/tests/ui/issues/issue-66667-function-cmp-cycle.stderr b/tests/ui/issues/issue-66667-function-cmp-cycle.stderr
@@ -19,7 +19,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-66667-function-cmp-cycle.rs:2:5
    |
 LL | fn first() {
-   |            - help: try adding a return type: `-> bool`
+   |           - help: try adding a return type: `-> bool`
 LL |     second == 1
    |     ^^^^^^^^^^^ expected `()`, found `bool`
 
@@ -44,7 +44,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-66667-function-cmp-cycle.rs:8:5
    |
 LL | fn second() {
-   |             - help: try adding a return type: `-> bool`
+   |            - help: try adding a return type: `-> bool`
 LL |     first == 1
    |     ^^^^^^^^^^ expected `()`, found `bool`
 
@@ -69,7 +69,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-66667-function-cmp-cycle.rs:14:5
    |
 LL | fn bar() {
-   |          - help: try adding a return type: `-> bool`
+   |         - help: try adding a return type: `-> bool`
 LL |     bar == 1
    |     ^^^^^^^^ expected `()`, found `bool`
 

diff --git a/tests/ui/lang-items/start_lang_item_args.missing_ret.stderr b/tests/ui/lang-items/start_lang_item_args.missing_ret.stderr
@@ -1,8 +1,8 @@
 error[E0308]: lang item `start` function has wrong type
-  --> $DIR/start_lang_item_args.rs:29:84
+  --> $DIR/start_lang_item_args.rs:29:83
    |
 LL | fn start<T>(_main: fn() -> T, _argc: isize, _argv: *const *const u8, _sigpipe: u8) {}
-   |                                                                                    ^ expected `isize`, found `()`
+   |                                                                                   ^ expected `isize`, found `()`
    |
    = note: expected signature `fn(fn() -> _, _, _, _) -> isize`
               found signature `fn(fn() -> _, _, _, _)`

diff --git a/tests/ui/loops/loop-break-value.stderr b/tests/ui/loops/loop-break-value.stderr
@@ -319,7 +319,7 @@ error[E0308]: mismatched types
   --> $DIR/loop-break-value.rs:159:15
    |
 LL | fn main() {
-   |           - expected `()` because of this return type
+   |          - expected `()` because of this return type
 ...
 LL |     loop { // point at the return type
    |     ---- this loop is expected to be of type `()`

diff --git a/tests/ui/mismatched_types/issue-19109.stderr b/tests/ui/mismatched_types/issue-19109.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-19109.rs:4:5
    |
 LL | fn function(t: &mut dyn Trait) {
-   |                                - help: try adding a return type: `-> *mut dyn Trait`
+   |                               - help: try adding a return type: `-> *mut dyn Trait`
 LL |     t as *mut dyn Trait
    |     ^^^^^^^^^^^^^^^^^^^ expected `()`, found `*mut dyn Trait`
    |

diff --git a/tests/ui/offset-of/offset-of-output-type.stderr b/tests/ui/offset-of/offset-of-output-type.stderr
@@ -42,7 +42,7 @@ error[E0308]: mismatched types
   --> $DIR/offset-of-output-type.rs:19:5
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 ...
 LL |     offset_of!(S, v)
    |     ^^^^^^^^^^^^^^^^ expected `()`, found `usize`

diff --git a/tests/ui/parser/recover-quantified-closure.stderr b/tests/ui/parser/recover-quantified-closure.stderr
@@ -25,10 +25,10 @@ LL |     for <Foo>::Bar in x {}
    = help: consider removing `for<...>`
 
 error: implicit types in closure signatures are forbidden when `for<...>` is present
-  --> $DIR/recover-quantified-closure.rs:2:25
+  --> $DIR/recover-quantified-closure.rs:2:24
    |
 LL |     for<'a> |x: &'a u8| *x + 1;
-   |     -------             ^
+   |     -------            ^
    |     |
    |     `for<...>` is here
 

diff --git a/tests/ui/proc-macro/issue-37788.stderr b/tests/ui/proc-macro/issue-37788.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-37788.rs:8:5
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |     // Test that constructing the `visible_parent_map` (in `cstore_impl.rs`) does not ICE.
 LL |     std::cell::Cell::new(0)
    |     ^^^^^^^^^^^^^^^^^^^^^^^- help: consider using a semicolon here: `;`

diff --git a/tests/ui/proc-macro/resolved-located-at.stderr b/tests/ui/proc-macro/resolved-located-at.stderr
@@ -10,7 +10,7 @@ error[E0308]: mismatched types
   --> $DIR/resolved-located-at.rs:7:27
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |     resolve_located_at!(a b)
    |                           ^ expected `()`, found `S`
    |

diff --git a/tests/ui/proc-macro/span-preservation.stderr b/tests/ui/proc-macro/span-preservation.stderr
@@ -38,31 +38,31 @@ error[E0308]: mismatched types
   --> $DIR/span-preservation.rs:39:5
    |
 LL | extern "C" fn bar() {
-   |                     - help: try adding a return type: `-> i32`
+   |                    - help: try adding a return type: `-> i32`
 LL |     0
    |     ^ expected `()`, found integer
 
 error[E0308]: mismatched types
   --> $DIR/span-preservation.rs:44:5
    |
 LL | extern "C" fn baz() {
-   |                     - help: try adding a return type: `-> i32`
+   |                    - help: try adding a return type: `-> i32`
 LL |     0
    |     ^ expected `()`, found integer
 
 error[E0308]: mismatched types
   --> $DIR/span-preservation.rs:49:5
    |
 LL | extern "Rust" fn rust_abi() {
-   |                             - help: try adding a return type: `-> i32`
+   |                            - help: try adding a return type: `-> i32`
 LL |     0
    |     ^ expected `()`, found integer
 
 error[E0308]: mismatched types
   --> $DIR/span-preservation.rs:54:5
    |
 LL | extern "\x43" fn c_abi_escaped() {
-   |                                  - help: try adding a return type: `-> i32`
+   |                                 - help: try adding a return type: `-> i32`
 LL |     0
    |     ^ expected `()`, found integer
 

diff --git a/tests/ui/return/return-struct.stderr b/tests/ui/return/return-struct.stderr
@@ -17,7 +17,7 @@ error[E0308]: mismatched types
   --> $DIR/return-struct.rs:15:5
    |
 LL | fn bar() {
-   |          - help: try adding a return type: `-> Age`
+   |         - help: try adding a return type: `-> Age`
 LL |     let mut age = 29;
 LL |     Age::Years(age, 55)
    |     ^^^^^^^^^^^^^^^^^^^ expected `()`, found `Age`
@@ -26,7 +26,7 @@ error[E0308]: mismatched types
   --> $DIR/return-struct.rs:20:5
    |
 LL | fn baz() {
-   |          - help: try adding a return type: `-> S`
+   |         - help: try adding a return type: `-> S`
 LL |     S
    |     ^ expected `()`, found `S`
 

diff --git a/tests/ui/suggestions/issue-83892.stderr b/tests/ui/suggestions/issue-83892.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/issue-83892.rs:9:15
    |
 LL | fn main() {
-   |           - expected `()` because of default return type
+   |          - expected `()` because of default return type
 LL |     match () {
 LL |         () => func()
    |               ^^^^^^ expected `()`, found `u8`

diff --git a/tests/ui/suggestions/return-closures.stderr b/tests/ui/suggestions/return-closures.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/return-closures.rs:3:5
    |
 LL | fn foo() {
-   |          - help: try adding a return type: `-> impl for<'a> Fn(&'a i32) -> i32`
+   |         - help: try adding a return type: `-> impl for<'a> Fn(&'a i32) -> i32`
 LL |
 LL |     |x: &i32| 1i32
    |     ^^^^^^^^^^^^^^ expected `()`, found closure
@@ -14,7 +14,7 @@ error[E0308]: mismatched types
   --> $DIR/return-closures.rs:9:5
    |
 LL | fn bar(i: impl Sized) {
-   |                       - help: a return type might be missing here: `-> _`
+   |                      - help: a return type might be missing here: `-> _`
 LL |
 LL |     || i
    |     ^^^^ expected `()`, found closure