Fix; correct placement of type inference error for method calls

Author: Jamesbarford

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -2975,6 +2975,7 @@ impl<'a, 'b, 'tcx> ArgsCtxt<'a, 'b, 'tcx> {
                 IsSuggestion(true),
                 callee_ty.peel_refs(),
                 self.call_ctxt.callee_expr.unwrap().hir_id,
+                None,
                 TraitsInScope,
                 |mut ctxt| ctxt.probe_for_similar_candidate(),
             )

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1794,6 +1794,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         self_ty,
                         expr.hir_id,
                         ProbeScope::TraitsInScope,
+                        Some(expr.span),
                     )
                 {
                     (pick.item, segment)

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -104,6 +104,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self_ty,
             call_expr_id,
             ProbeScope::TraitsInScope,
+            None,
         ) {
             Ok(pick) => {
                 pick.maybe_emit_unstable_name_collision_hint(
@@ -188,7 +189,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ProbeScope::TraitsInScope
         };
 
-        let pick = self.lookup_probe(segment.ident, self_ty, call_expr, scope)?;
+        let pick = self.lookup_probe(segment.ident, self_ty, call_expr, self_expr, scope)?;
 
         self.lint_edition_dependent_dot_call(
             self_ty, segment, span, call_expr, self_expr, &pick, args,
@@ -215,6 +216,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     segment.ident,
                     trait_type,
                     call_expr,
+                    self_expr,
                     ProbeScope::TraitsInScope,
                 ) {
                     Ok(ref new_pick) if pick.differs_from(new_pick) => {
@@ -283,6 +285,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         method_name: Ident,
         self_ty: Ty<'tcx>,
         call_expr: &hir::Expr<'_>,
+        self_expr: &hir::Expr<'_>,
         scope: ProbeScope,
     ) -> probe::PickResult<'tcx> {
         let pick = self.probe_for_name(
@@ -293,7 +296,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self_ty,
             call_expr.hir_id,
             scope,
+            Some(self_expr.span),
         )?;
+
         pick.maybe_emit_unstable_name_collision_hint(self.tcx, method_name.span, call_expr.hir_id);
         Ok(pick)
     }
@@ -314,6 +319,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self_ty,
             call_expr.hir_id,
             scope,
+            None,
         )?;
         Ok(pick)
     }
@@ -533,6 +539,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self_ty,
             expr_id,
             ProbeScope::TraitsInScope,
+            Some(self_ty_span),
         );
         let pick = match (pick, struct_variant) {
             // Fall back to a resolution that will produce an error later.

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -296,6 +296,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 IsSuggestion(true),
                 self_ty,
                 scope_expr_id,
+                None,
                 ProbeScope::AllTraits,
                 |probe_cx| Ok(probe_cx.candidate_method_names(candidate_filter)),
             )
@@ -311,6 +312,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     IsSuggestion(true),
                     self_ty,
                     scope_expr_id,
+                    None,
                     ProbeScope::AllTraits,
                     |probe_cx| probe_cx.pick(),
                 )
@@ -330,6 +332,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_ty: Ty<'tcx>,
         scope_expr_id: HirId,
         scope: ProbeScope,
+        self_expr_span: Option<Span>,
     ) -> PickResult<'tcx> {
         self.probe_op(
             item_name.span,
@@ -339,6 +342,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             is_suggestion,
             self_ty,
             scope_expr_id,
+            self_expr_span,
             scope,
             |probe_cx| probe_cx.pick(),
         )
@@ -363,6 +367,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             is_suggestion,
             self_ty,
             scope_expr_id,
+            None,
             scope,
             |probe_cx| {
                 Ok(probe_cx
@@ -383,6 +388,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         is_suggestion: IsSuggestion,
         self_ty: Ty<'tcx>,
         scope_expr_id: HirId,
+        self_expr: Option<Span>,
         scope: ProbeScope,
         op: OP,
     ) -> Result<R, MethodError<'tcx>>
@@ -488,11 +494,10 @@ 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,
+                            self_expr.unwrap_or(span),
                             ty.into(),
                             TypeAnnotationNeeded::E0282,
                             !raw_ptr_call,

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -2114,6 +2114,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             rcvr_ty,
                             expr_id,
                             ProbeScope::TraitsInScope,
+                            None,
                         )
                         .is_ok()
             })
@@ -3176,6 +3177,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 deref_ty,
                 ty.hir_id,
                 ProbeScope::TraitsInScope,
+                None,
             ) {
                 if deref_ty.is_suggestable(self.tcx, true)
                     // If this method receives `&self`, then the provided

tests/ui/autoref-autoderef/deref-ambiguity-becomes-nonambiguous.stderr

@@ -5,7 +5,7 @@ LL |     let var_fn = Value::wrap();
    |         ^^^^^^
 ...
 LL |     let _ = var_fn.clone();
-   |                    ----- type must be known at this point
+   |             ------ type must be known at this point
    |
 help: consider giving `var_fn` an explicit type, where the placeholders `_` are specified
    |

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
    |

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
    |

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
    |

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
    |