} else {
let trait_ref = trait_predicate.to_poly_trait_ref();
- let mut err = struct_span_err!(self.tcx.sess, span, E0277,
- "the trait bound `{}` is not satisfied",
- trait_ref.to_predicate());
- err.span_label(span, &format!("the trait `{}` is not implemented \
- for `{}`",
- trait_ref,
- trait_ref.self_ty()));
+ let (post_message, pre_message) =
+ if let ObligationCauseCode::BuiltinDerivedObligation(ref data)
+ = obligation.cause.code {
+ let parent_trait_ref = self.resolve_type_vars_if_possible(
+ &data.parent_trait_ref);
+ (format!(" in `{}`", parent_trait_ref.0.self_ty()),
+ format!("within `{}`, ", parent_trait_ref.0.self_ty()))
+ } else {
+ (String::new(), String::new())
+ };
+ let mut err = struct_span_err!(
+ self.tcx.sess,
+ span,
+ E0277,
+ "the trait bound `{}` is not satisfied{}",
+ trait_ref.to_predicate(),
+ post_message);
+ err.span_label(span,
+ &format!("{}the trait `{}` is not \
+ implemented for `{}`",
+ pre_message,
+ trait_ref,
+ trait_ref.self_ty()));
// Try to report a help message
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+use std::path::Path;
+
trait Foo {
fn bar(&self);
}
foo.bar();
}
+fn f(p: Path) { }
+//~^ ERROR the trait bound `[u8]: std::marker::Sized` is not satisfied in `std::path::Path`
+//~| NOTE within `std::path::Path`, the trait `std::marker::Sized` is not implemented for `[u8]`
+//~| NOTE `[u8]` does not have a constant size known at compile-time
+//~| NOTE required because it appears within the type `std::path::Path`
+//~| NOTE all local variables must have a statically known size
+
fn main() {
some_func(5i32);
//~^ ERROR the trait bound `i32: Foo` is not satisfied