use try_structurally_resolve_type for method receiver

lcnr · lcnr · commit 6b379b560df4 · 2025-09-26T16:33:15.000+02:00
We'll still error due to the `opt_bad_ty` of `method_autoderef_steps`.
This slightly worsens the span of `infer_var.method()` which is now the
same as for `Box::new(infer_var).method()`.

Unlike `structurally_resolve_type`, `probe_op` does not check whether
the infcx is already tainted, so this results in 2 previously not emitted
errors.
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1633,8 +1633,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Expectation<'tcx>,
     ) -> Ty<'tcx> {
         let rcvr_t = self.check_expr(rcvr);
-        // no need to check for bot/err -- callee does that
-        let rcvr_t = self.structurally_resolve_type(rcvr.span, rcvr_t);
+        let rcvr_t = self.try_structurally_resolve_type(rcvr.span, rcvr_t);
 
         match self.lookup_method(rcvr_t, segment, segment.ident.span, expr, rcvr, args) {
             Ok(method) => {
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -486,6 +486,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ty::Infer(ty::TyVar(_)) => {
                         let raw_ptr_call = bad_ty.reached_raw_pointer
                             && !self.tcx.features().arbitrary_self_types();
+                        // FIXME: Ideally we'd use the span of the self-expr here,
+                        // not of the method path.
                         let mut err = self.err_ctxt().emit_inference_failure_err(
                             self.body_id,
                             span,
diff --git a/tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.next.stderr b/tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.next.stderr
@@ -5,7 +5,7 @@ LL |     needs_foo(|x| {
    |                ^
 ...
 LL |         x.to_string();
-   |         - type must be known at this point
+   |           --------- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/impl-trait/call_method_ambiguous.next.stderr b/tests/ui/impl-trait/call_method_ambiguous.next.stderr
@@ -5,7 +5,7 @@ LL |         let mut iter = foo(n - 1, m);
    |             ^^^^^^^^
 LL |
 LL |         assert_eq!(iter.get(), 1);
-   |                    ---- type must be known at this point
+   |                         --- type must be known at this point
    |
 help: consider giving `iter` an explicit type
    |
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl.next.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl.next.stderr
@@ -5,7 +5,7 @@ LL |         let x = my_foo();
    |             ^
 LL |
 LL |         x.my_debug();
-   |         - type must be known at this point
+   |           -------- type must be known at this point
    |
 help: consider giving `x` an explicit type
    |
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_ref.next.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.next.stderr
@@ -5,7 +5,7 @@ LL |         let x = my_foo();
    |             ^
 LL |
 LL |         x.my_debug();
-   |         - type must be known at this point
+   |           -------- type must be known at this point
    |
 help: consider giving `x` an explicit type
    |
diff --git a/tests/ui/impl-trait/hidden-type-is-opaque-2.default.stderr b/tests/ui/impl-trait/hidden-type-is-opaque-2.default.stderr
@@ -5,7 +5,7 @@ LL |     Thunk::new(|mut cont| {
    |                 ^^^^^^^^
 LL |
 LL |         cont.reify_as();
-   |         ---- type must be known at this point
+   |              -------- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -19,7 +19,7 @@ LL |     Thunk::new(|mut cont| {
    |                 ^^^^^^^^
 LL |
 LL |         cont.reify_as();
-   |         ---- type must be known at this point
+   |              -------- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/impl-trait/hidden-type-is-opaque-2.next.stderr b/tests/ui/impl-trait/hidden-type-is-opaque-2.next.stderr
@@ -5,7 +5,7 @@ LL |     Thunk::new(|mut cont| {
    |                 ^^^^^^^^
 LL |
 LL |         cont.reify_as();
-   |         ---- type must be known at this point
+   |              -------- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -19,7 +19,7 @@ LL |     Thunk::new(|mut cont| {
    |                 ^^^^^^^^
 LL |
 LL |         cont.reify_as();
-   |         ---- type must be known at this point
+   |              -------- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/impl-trait/method-resolution4.next.stderr b/tests/ui/impl-trait/method-resolution4.next.stderr
@@ -1,8 +1,8 @@
 error[E0282]: type annotations needed
-  --> $DIR/method-resolution4.rs:13:9
+  --> $DIR/method-resolution4.rs:13:20
    |
 LL |         foo(false).next().unwrap();
-   |         ^^^^^^^^^^ cannot infer type
+   |                    ^^^^ cannot infer type
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/impl-trait/recursive-bound-eval.next.stderr b/tests/ui/impl-trait/recursive-bound-eval.next.stderr
@@ -1,8 +1,8 @@
 error[E0282]: type annotations needed
-  --> $DIR/recursive-bound-eval.rs:20:13
+  --> $DIR/recursive-bound-eval.rs:20:28
    |
 LL |     move || recursive_fn().parse()
-   |             ^^^^^^^^^^^^^^ cannot infer type
+   |                            ^^^^^ cannot infer type
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/inference/need_type_info/incompat-call-after-qualified-path-0.stderr b/tests/ui/inference/need_type_info/incompat-call-after-qualified-path-0.stderr
@@ -2,7 +2,7 @@ error[E0282]: type annotations needed
   --> $DIR/incompat-call-after-qualified-path-0.rs:21:6
    |
 LL |   f(|a, b| a.cmp(b));
-   |      ^     - type must be known at this point
+   |      ^       --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/inference/need_type_info/incompat-call-after-qualified-path-1.stderr b/tests/ui/inference/need_type_info/incompat-call-after-qualified-path-1.stderr
@@ -2,7 +2,7 @@ error[E0282]: type annotations needed
   --> $DIR/incompat-call-after-qualified-path-1.rs:25:6
    |
 LL |   f(|a, b| a.cmp(b));
-   |      ^     - type must be known at this point
+   |      ^       --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/issues/issue-2151.stderr b/tests/ui/issues/issue-2151.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
 LL |     let x = panic!();
    |         ^
 LL |     x.clone();
-   |     - type must be known at this point
+   |       ----- type must be known at this point
    |
 help: consider giving `x` an explicit type
    |
diff --git a/tests/ui/lazy-type-alias-impl-trait/branches3.stderr b/tests/ui/lazy-type-alias-impl-trait/branches3.stderr
@@ -2,7 +2,7 @@ error[E0282]: type annotations needed
   --> $DIR/branches3.rs:9:10
    |
 LL |         |s| s.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -13,7 +13,7 @@ error[E0282]: type annotations needed
   --> $DIR/branches3.rs:18:10
    |
 LL |         |s| s.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -24,7 +24,7 @@ error[E0282]: type annotations needed
   --> $DIR/branches3.rs:26:10
    |
 LL |         |s| s.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -35,7 +35,7 @@ error[E0282]: type annotations needed
   --> $DIR/branches3.rs:33:10
    |
 LL |         |s| s.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/proc-macro/quote/not-repeatable.rs b/tests/ui/proc-macro/quote/not-repeatable.rs
@@ -8,5 +8,7 @@ struct Ipv4Addr;
 
 fn main() {
     let ip = Ipv4Addr;
-    let _ = quote! { $($ip)* }; //~ ERROR the method `quote_into_iter` exists for struct `Ipv4Addr`, but its trait bounds were not satisfied
+    let _ = quote! { $($ip)* };
+    //~^ ERROR the method `quote_into_iter` exists for struct `Ipv4Addr`, but its trait bounds were not satisfied
+    //~| ERROR type annotations needed
 }
diff --git a/tests/ui/proc-macro/quote/not-repeatable.stderr b/tests/ui/proc-macro/quote/not-repeatable.stderr
@@ -20,6 +20,13 @@ note: the traits `Iterator` and `ToTokens` must be implemented
   --> $SRC_DIR/proc_macro/src/to_tokens.rs:LL:COL
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error: aborting due to 1 previous error
+error[E0282]: type annotations needed
+  --> $DIR/not-repeatable.rs:11:13
+   |
+LL |     let _ = quote! { $($ip)* };
+   |             ^^^^^^^^^^^^^^^^^^ cannot infer type
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0599`.
+Some errors have detailed explanations: E0282, E0599.
+For more information about an error, try `rustc --explain E0282`.
diff --git a/tests/ui/repeat-expr/copy-inference-side-effects-are-lazy.stderr b/tests/ui/repeat-expr/copy-inference-side-effects-are-lazy.stderr
@@ -5,9 +5,9 @@ LL |     let x = [Foo(PhantomData); 2];
    |         ^
 LL |
 LL |     extract(x).max(2);
-   |     ---------- type must be known at this point
+   |                --- type must be known at this point
    |
-help: consider giving `x` an explicit type, where the type for type parameter `T` is specified
+help: consider giving `x` an explicit type, where the placeholders `_` are specified
    |
 LL |     let x: [Foo<T>; 2] = [Foo(PhantomData); 2];
    |          +++++++++++++
diff --git a/tests/ui/span/issue-42234-unknown-receiver-type.stderr b/tests/ui/span/issue-42234-unknown-receiver-type.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
 LL |     let x: Option<_> = None;
    |                        ^^^^ cannot infer type of the type parameter `T` declared on the enum `Option`
 LL |     x.unwrap().method_that_could_exist_on_some_type();
-   |     ---------- type must be known at this point
+   |                ------------------------------------ type must be known at this point
    |
 help: consider specifying the generic argument
    |
@@ -16,6 +16,8 @@ error[E0282]: type annotations needed
    |
 LL |         .sum::<_>()
    |          ^^^ cannot infer type of the type parameter `S` declared on the method `sum`
+LL |         .to_string()
+   |          --------- type must be known at this point
    |
 
 error: aborting due to 2 previous errors
diff --git a/tests/ui/type-alias-impl-trait/closures_in_branches.stderr b/tests/ui/type-alias-impl-trait/closures_in_branches.stderr
@@ -2,7 +2,7 @@ error[E0282]: type annotations needed
   --> $DIR/closures_in_branches.rs:8:10
    |
 LL |         |x| x.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
@@ -13,7 +13,7 @@ error[E0282]: type annotations needed
   --> $DIR/closures_in_branches.rs:22:10
    |
 LL |         |x| x.len()
-   |          ^  - type must be known at this point
+   |          ^    --- type must be known at this point
    |
 help: consider giving this closure parameter an explicit type
    |
diff --git a/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.next.stderr b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.next.stderr
@@ -1,8 +1,8 @@
 error[E0282]: type annotations needed
-  --> $DIR/method_resolution_trait_method_from_opaque.rs:28:9
+  --> $DIR/method_resolution_trait_method_from_opaque.rs:28:18
    |
 LL |         self.bar.next().unwrap();
-   |         ^^^^^^^^ cannot infer type
+   |                  ^^^^ cannot infer type
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/type-inference/regression-issue-81317.stderr b/tests/ui/type-inference/regression-issue-81317.stderr
@@ -5,7 +5,7 @@ LL |     let iv = S ^ index.into();
    |         ^^
 LL |
 LL |     &iv.to_bytes_be();
-   |      -- type must be known at this point
+   |         ----------- type must be known at this point
    |
 help: consider giving `iv` an explicit type
    |
diff --git a/tests/ui/typeck/issue-13853.rs b/tests/ui/typeck/issue-13853.rs
@@ -25,7 +25,7 @@ impl Node for Stuff {
 
 fn iterate<N: Node, G: Graph<N>>(graph: &G) {
     for node in graph.iter() { //~ ERROR no method named `iter` found
-        node.zomg();
+        node.zomg(); //~ ERROR type annotations needed
     }
 }
 
diff --git a/tests/ui/typeck/issue-13853.stderr b/tests/ui/typeck/issue-13853.stderr
@@ -17,6 +17,12 @@ error[E0599]: no method named `iter` found for reference `&G` in the current sco
 LL |     for node in graph.iter() {
    |                       ^^^^ method not found in `&G`
 
+error[E0282]: type annotations needed
+  --> $DIR/issue-13853.rs:28:14
+   |
+LL |         node.zomg();
+   |              ^^^^ cannot infer type
+
 error[E0308]: mismatched types
   --> $DIR/issue-13853.rs:37:13
    |
@@ -37,7 +43,7 @@ help: consider borrowing here
 LL |     iterate(&graph);
    |             +
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0308, E0599.
-For more information about an error, try `rustc --explain E0308`.
+Some errors have detailed explanations: E0282, E0308, E0599.
+For more information about an error, try `rustc --explain E0282`.

Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ LL \| needs_foo(\|x\| {`
`5`	`5`	`\| ^`
`6`	`6`	`...`
`7`	`7`	`LL \| x.to_string();`
`8`		`- \| - type must be known at this point`
	`8`	`+ \| --------- type must be known at this point`
`9`	`9`	`\|`
`10`	`10`	`help: consider giving this closure parameter an explicit type`
`11`	`11`	`\|`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ LL \| let mut iter = foo(n - 1, m);`
`5`	`5`	`\| ^^^^^^^^`
`6`	`6`	`LL \|`
`7`	`7`	`LL \| assert_eq!(iter.get(), 1);`
`8`		`- \| ---- type must be known at this point`
	`8`	`+ \| --- type must be known at this point`
`9`	`9`	`\|`
`10`	`10`	help: consider giving `iter` an explicit type
`11`	`11`	`\|`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ LL \| let x = my_foo();`
`5`	`5`	`\| ^`
`6`	`6`	`LL \|`
`7`	`7`	`LL \| x.my_debug();`
`8`		`- \| - type must be known at this point`
	`8`	`+ \| -------- type must be known at this point`
`9`	`9`	`\|`
`10`	`10`	help: consider giving `x` an explicit type
`11`	`11`	`\|`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ LL \| Thunk::new(\|mut cont\| {`
`5`	`5`	`\| ^^^^^^^^`
`6`	`6`	`LL \|`
`7`	`7`	`LL \| cont.reify_as();`
`8`		`- \| ---- type must be known at this point`
	`8`	`+ \| -------- type must be known at this point`
`9`	`9`	`\|`
`10`	`10`	`help: consider giving this closure parameter an explicit type`
`11`	`11`	`\|`
`@@ -19,7 +19,7 @@ LL \| Thunk::new(\|mut cont\| {`
`19`	`19`	`\| ^^^^^^^^`
`20`	`20`	`LL \|`
`21`	`21`	`LL \| cont.reify_as();`
`22`		`- \| ---- type must be known at this point`
	`22`	`+ \| -------- type must be known at this point`
`23`	`23`	`\|`
`24`	`24`	`help: consider giving this closure parameter an explicit type`
`25`	`25`	`\|`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`error[E0282]: type annotations needed`
`2`		`- --> $DIR/method-resolution4.rs:13:9`
	`2`	`+ --> $DIR/method-resolution4.rs:13:20`
`3`	`3`	`\|`
`4`	`4`	`LL \| foo(false).next().unwrap();`
`5`		`- \| ^^^^^^^^^^ cannot infer type`
	`5`	`+ \| ^^^^ cannot infer type`
`6`	`6`
`7`	`7`	`error: aborting due to 1 previous error`
`8`	`8`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`error[E0282]: type annotations needed`
`2`		`- --> $DIR/recursive-bound-eval.rs:20:13`
	`2`	`+ --> $DIR/recursive-bound-eval.rs:20:28`
`3`	`3`	`\|`
`4`	`4`	`LL \| move \|\| recursive_fn().parse()`
`5`		`- \| ^^^^^^^^^^^^^^ cannot infer type`
	`5`	`+ \| ^^^^^ cannot infer type`
`6`	`6`
`7`	`7`	`error: aborting due to 1 previous error`
`8`	`8`