diff --git a/src/librustc/middle/traits/error_reporting.rs b/src/librustc/middle/traits/error_reporting.rs index 1b5719d3d42e5..7d69df73cd2ad 100644 --- a/src/librustc/middle/traits/error_reporting.rs +++ b/src/librustc/middle/traits/error_reporting.rs @@ -56,7 +56,10 @@ pub fn report_projection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>, { let predicate = infcx.resolve_type_vars_if_possible(&obligation.predicate); - if !predicate.references_error() { + // The ty_err created by normalize_to_error can end up being unified + // into all obligations - we still have to report an error in that + // case. + if !infcx.tcx.sess.has_errors() || !predicate.references_error() { span_err!(infcx.tcx.sess, obligation.cause.span, E0271, "type mismatch resolving `{}`: {}", predicate.user_string(infcx.tcx), @@ -183,7 +186,8 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>, let trait_predicate = infcx.resolve_type_vars_if_possible(trait_predicate); - if !trait_predicate.references_error() { + if !infcx.tcx.sess.has_errors() || + !trait_predicate.references_error() { let trait_ref = trait_predicate.to_poly_trait_ref(); span_err!(infcx.tcx.sess, obligation.cause.span, E0277, "the trait `{}` is not implemented for the type `{}`", diff --git a/src/librustc/middle/traits/project.rs b/src/librustc/middle/traits/project.rs index 8ae7ad029ac3f..f6bde80e29875 100644 --- a/src/librustc/middle/traits/project.rs +++ b/src/librustc/middle/traits/project.rs @@ -408,7 +408,10 @@ fn opt_normalize_projection_type<'a,'b,'tcx>( } /// in various error cases, we just set ty_err and return an obligation -/// that, when fulfilled, will lead to an error +/// that, when fulfilled, will lead to an error. +/// +/// FIXME: the ty_err created here can enter the obligation we create, +/// leading to error messages involving ty_err. fn normalize_to_error<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>, projection_ty: ty::ProjectionTy<'tcx>, cause: ObligationCause<'tcx>, diff --git a/src/test/compile-fail/issue-25076.rs b/src/test/compile-fail/issue-25076.rs new file mode 100644 index 0000000000000..40f3b72849612 --- /dev/null +++ b/src/test/compile-fail/issue-25076.rs @@ -0,0 +1,21 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +struct S; + +trait InOut { type Out; } + +fn do_fold>(init: B, f: F) {} + +fn bot() -> T { loop {} } + +fn main() { + do_fold(bot(), ()); //~ ERROR is not implemented for the type `()` +}