Point at the def span of trait refs E0277

rust-lang · Jan 8, 2020 · 0dcdbae · 0dcdbae
1 parent c556151
commit 0dcdbae
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Showing 8 changed files with 71 additions and 13 deletions.
diff --git a/src/librustc/infer/error_reporting/mod.rs b/src/librustc/infer/error_reporting/mod.rs
@@ -71,6 +71,7 @@ use rustc_hir::Node;
 use errors::{
     pluralize, struct_span_err, Applicability, DiagnosticBuilder, DiagnosticStyledString,
 };
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_error_codes::*;
 use rustc_span::{DesugaringKind, Pos, Span};
 use rustc_target::spec::abi;
@@ -1362,9 +1363,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 let kind = match t.kind {
                     ty::Closure(..) => "closure",
                     ty::Opaque(..) => "opaque type",
+                    ty::Generator(..) => "generator",
+                    ty::Foreign(..) => "foreign type",
                     _ => "",
                 };
-                if let ty::Closure(def_id, _) | ty::Opaque(def_id, _) = t.kind {
+                if let ty::Closure(def_id, _)
+                | ty::Opaque(def_id, _)
+                | ty::Generator(def_id, ..)
+                | ty::Foreign(def_id) = t.kind
+                {
                     let span = self.tcx.def_span(def_id);
                     // Avoid cluttering the output when the "found" and error span overlap:
                     //

diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
@@ -446,7 +446,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 flags.push((sym::from_method, Some(method.to_string())));
             }
         }
-        if let Some(t) = self.get_parent_trait_ref(&obligation.cause.code) {
+        if let Some((t, _)) = self.get_parent_trait_ref(&obligation.cause.code) {
             flags.push((sym::parent_trait, Some(t)));
         }
 
@@ -665,13 +665,28 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     }
 
     /// Gets the parent trait chain start
-    fn get_parent_trait_ref(&self, code: &ObligationCauseCode<'tcx>) -> Option<String> {
+    fn get_parent_trait_ref(
+        &self,
+        code: &ObligationCauseCode<'tcx>,
+    ) -> Option<(String, Option<Span>)> {
         match code {
             &ObligationCauseCode::BuiltinDerivedObligation(ref data) => {
                 let parent_trait_ref = self.resolve_vars_if_possible(&data.parent_trait_ref);
                 match self.get_parent_trait_ref(&data.parent_code) {
                     Some(t) => Some(t),
-                    None => Some(parent_trait_ref.skip_binder().self_ty().to_string()),
+                    None => {
+                        let ty = parent_trait_ref.skip_binder().self_ty();
+                        let span = if let ty::Closure(def_id, _)
+                        | ty::Opaque(def_id, _)
+                        | ty::Generator(def_id, ..)
+                        | ty::Foreign(def_id) = ty.kind
+                        {
+                            Some(self.tcx.def_span(def_id))
+                        } else {
+                            None
+                        };
+                        Some((ty.to_string(), span))
+                    }
                 }
             }
             _ => None,
@@ -719,9 +734,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                             return;
                         }
                         let trait_ref = trait_predicate.to_poly_trait_ref();
-                        let (post_message, pre_message) = self
+                        let (post_message, pre_message, type_def) = self
                             .get_parent_trait_ref(&obligation.cause.code)
-                            .map(|t| (format!(" in `{}`", t), format!("within `{}`, ", t)))
+                            .map(|(t, s)| {
+                                (
+                                    format!(" in `{}`", t),
+                                    format!("within `{}`, ", t),
+                                    s.map(|s| (format!("within this `{}`", t), s)),
+                                )
+                            })
                             .unwrap_or_default();
 
                         let OnUnimplementedNote { message, label, note, enclosing_scope } =
@@ -795,6 +816,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         } else {
                             err.span_label(span, explanation);
                         }
+                        if let Some((msg, span)) = type_def {
+                            err.span_label(span, &msg);
+                        }
                         if let Some(ref s) = note {
                             // If it has a custom `#[rustc_on_unimplemented]` note, let's display it
                             err.note(s.as_str());

diff --git a/src/test/ui/async-await/issue-64130-3-other.stderr b/src/test/ui/async-await/issue-64130-3-other.stderr
@@ -3,6 +3,9 @@ error[E0277]: the trait bound `Foo: Qux` is not satisfied in `impl std::future::
    |
 LL | fn is_qux<T: Qux>(t: T) { }
    |    ------    --- required by this bound in `is_qux`
+LL | 
+LL | async fn bar() {
+   |                - within this `impl std::future::Future`
 ...
 LL |     is_qux(bar());
    |     ^^^^^^ within `impl std::future::Future`, the trait `Qux` is not implemented for `Foo`

diff --git a/src/test/ui/impl-trait/auto-trait-leak.stderr b/src/test/ui/impl-trait/auto-trait-leak.stderr
@@ -77,6 +77,9 @@ LL | fn send<T: Send>(_: T) {}
 ...
 LL |     send(cycle2().clone());
    |     ^^^^ `std::rc::Rc<std::string::String>` cannot be sent between threads safely
+...
+LL | fn cycle2() -> impl Clone {
+   |                ---------- within this `impl std::clone::Clone`
    |
    = help: within `impl std::clone::Clone`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::string::String>`
    = note: required because it appears within the type `impl std::clone::Clone`

diff --git a/src/test/ui/impl-trait/auto-trait-leak2.stderr b/src/test/ui/impl-trait/auto-trait-leak2.stderr
@@ -1,6 +1,9 @@
 error[E0277]: `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
   --> $DIR/auto-trait-leak2.rs:13:5
    |
+LL | fn before() -> impl Fn(i32) {
+   |                ------------ within this `impl std::ops::Fn<(i32,)>`
+...
 LL | fn send<T: Send>(_: T) {}
    |    ----    ---- required by this bound in `send`
 ...
@@ -19,6 +22,9 @@ LL | fn send<T: Send>(_: T) {}
 ...
 LL |     send(after());
    |     ^^^^ `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
+...
+LL | fn after() -> impl Fn(i32) {
+   |               ------------ within this `impl std::ops::Fn<(i32,)>`
    |
    = help: within `impl std::ops::Fn<(i32,)>`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
    = note: required because it appears within the type `[closure@$DIR/auto-trait-leak2.rs:24:5: 24:22 p:std::rc::Rc<std::cell::Cell<i32>>]`

diff --git a/src/test/ui/kindck/kindck-nonsendable-1.stderr b/src/test/ui/kindck/kindck-nonsendable-1.stderr
@@ -5,7 +5,9 @@ LL | fn bar<F:FnOnce() + Send>(_: F) { }
    |    ---              ---- required by this bound in `bar`
 ...
 LL |     bar(move|| foo(x));
-   |     ^^^ `std::rc::Rc<usize>` cannot be sent between threads safely
+   |     ^^^ ------------- within this `[closure@$DIR/kindck-nonsendable-1.rs:9:9: 9:22 x:std::rc::Rc<usize>]`
+   |     |
+   |     `std::rc::Rc<usize>` cannot be sent between threads safely
    |
    = help: within `[closure@$DIR/kindck-nonsendable-1.rs:9:9: 9:22 x:std::rc::Rc<usize>]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<usize>`
    = note: required because it appears within the type `[closure@$DIR/kindck-nonsendable-1.rs:9:9: 9:22 x:std::rc::Rc<usize>]`

diff --git a/src/test/ui/no-send-res-ports.stderr b/src/test/ui/no-send-res-ports.stderr
@@ -1,13 +1,20 @@
 error[E0277]: `std::rc::Rc<()>` cannot be sent between threads safely
   --> $DIR/no-send-res-ports.rs:29:5
    |
-LL |     thread::spawn(move|| {
-   |     ^^^^^^^^^^^^^ `std::rc::Rc<()>` cannot be sent between threads safely
+LL |       thread::spawn(move|| {
+   |  _____^^^^^^^^^^^^^_-
+   | |     |
+   | |     `std::rc::Rc<()>` cannot be sent between threads safely
+LL | |
+LL | |         let y = x;
+LL | |         println!("{:?}", y);
+LL | |     });
+   | |_____- within this `[closure@$DIR/no-send-res-ports.rs:29:19: 33:6 x:main::Foo]`
    | 
   ::: $SRC_DIR/libstd/thread/mod.rs:LL:COL
    |
-LL |     F: Send + 'static,
-   |        ---- required by this bound in `std::thread::spawn`
+LL |       F: Send + 'static,
+   |          ---- required by this bound in `std::thread::spawn`
    |
    = help: within `[closure@$DIR/no-send-res-ports.rs:29:19: 33:6 x:main::Foo]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`
    = note: required because it appears within the type `Port<()>`

diff --git a/src/test/ui/not-clone-closure.stderr b/src/test/ui/not-clone-closure.stderr
@@ -1,8 +1,14 @@
 error[E0277]: the trait bound `S: std::clone::Clone` is not satisfied in `[closure@$DIR/not-clone-closure.rs:7:17: 9:6 a:S]`
   --> $DIR/not-clone-closure.rs:11:23
    |
-LL |     let hello = hello.clone();
-   |                       ^^^^^ within `[closure@$DIR/not-clone-closure.rs:7:17: 9:6 a:S]`, the trait `std::clone::Clone` is not implemented for `S`
+LL |       let hello = move || {
+   |  _________________-
+LL | |         println!("Hello {}", a.0);
+LL | |     };
+   | |_____- within this `[closure@$DIR/not-clone-closure.rs:7:17: 9:6 a:S]`
+LL | 
+LL |       let hello = hello.clone();
+   |                         ^^^^^ within `[closure@$DIR/not-clone-closure.rs:7:17: 9:6 a:S]`, the trait `std::clone::Clone` is not implemented for `S`
    |
    = note: required because it appears within the type `[closure@$DIR/not-clone-closure.rs:7:17: 9:6 a:S]`