diff --git a/src/librustc/middle/infer/error_reporting.rs b/src/librustc/middle/infer/error_reporting.rs index 36229a558e955..03e76f5ee2573 100644 --- a/src/librustc/middle/infer/error_reporting.rs +++ b/src/librustc/middle/infer/error_reporting.rs @@ -373,8 +373,9 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> { fn report_and_explain_type_error(&self, trace: TypeTrace<'tcx>, terr: &ty::type_err<'tcx>) { + let span = trace.origin.span(); self.report_type_error(trace, terr); - ty::note_and_explain_type_err(self.tcx, terr); + ty::note_and_explain_type_err(self.tcx, terr, span); } /// Returns a string of the form "expected `{}`, found `{}`", or None if this is a derived @@ -812,7 +813,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> { } self.give_suggestion(same_regions); for &(ref trace, terr) in trace_origins { - self.report_type_error(trace.clone(), &terr); + self.report_and_explain_type_error(trace.clone(), &terr); } } diff --git a/src/librustc/middle/infer/mod.rs b/src/librustc/middle/infer/mod.rs index b11e25c059d08..0f62b440bf32d 100644 --- a/src/librustc/middle/infer/mod.rs +++ b/src/librustc/middle/infer/mod.rs @@ -987,7 +987,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { error_str)); if let Some(err) = err { - ty::note_and_explain_type_err(self.tcx, err) + ty::note_and_explain_type_err(self.tcx, err, sp) } } } diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs index 1123c9236312a..76581529a46f0 100644 --- a/src/librustc/middle/ty.rs +++ b/src/librustc/middle/ty.rs @@ -5096,7 +5096,7 @@ pub fn type_err_to_str<'tcx>(cx: &ctxt<'tcx>, err: &type_err<'tcx>) -> String { } } -pub fn note_and_explain_type_err(cx: &ctxt, err: &type_err) { +pub fn note_and_explain_type_err<'tcx>(cx: &ctxt<'tcx>, err: &type_err<'tcx>, sp: Span) { match *err { terr_regions_does_not_outlive(subregion, superregion) => { note_and_explain_region(cx, "", subregion, "..."); @@ -5127,6 +5127,16 @@ pub fn note_and_explain_type_err(cx: &ctxt, err: &type_err) { "expected concrete lifetime is ", conc_region, ""); } + terr_sorts(values) => { + let expected_str = ty_sort_string(cx, values.expected); + let found_str = ty_sort_string(cx, values.found); + if expected_str == found_str && expected_str == "closure" { + cx.sess.span_note(sp, &format!("no two closures, even if identical, have the same \ + type")); + cx.sess.span_help(sp, &format!("consider boxing your closure and/or \ + using it as a trait object")); + } + } _ => {} } } diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs index 3e3e5e17963cd..698b681bd55ae 100644 --- a/src/librustc/session/mod.rs +++ b/src/librustc/session/mod.rs @@ -155,7 +155,7 @@ impl Session { self.diagnostic().handler().note(msg) } pub fn help(&self, msg: &str) { - self.diagnostic().handler().note(msg) + self.diagnostic().handler().help(msg) } pub fn opt_span_bug(&self, opt_sp: Option, msg: &str) -> ! { match opt_sp { diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 156fbfede9c98..ce4eab9988dd4 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -3709,7 +3709,7 @@ fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>, .ty_to_string( actual_structure_type), type_error_description); - ty::note_and_explain_type_err(tcx, &type_error); + ty::note_and_explain_type_err(tcx, &type_error, path.span); } } } diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs index 9d6c04b1ad49d..be3fc860b2b12 100644 --- a/src/librustc_typeck/lib.rs +++ b/src/librustc_typeck/lib.rs @@ -200,7 +200,7 @@ fn require_same_types<'a, 'tcx, M>(tcx: &ty::ctxt<'tcx>, msg(), ty::type_err_to_str(tcx, terr)); - ty::note_and_explain_type_err(tcx, terr); + ty::note_and_explain_type_err(tcx, terr, span); false } } diff --git a/src/test/compile-fail/issue-24036.rs b/src/test/compile-fail/issue-24036.rs new file mode 100644 index 0000000000000..3c8a64eaf7de4 --- /dev/null +++ b/src/test/compile-fail/issue-24036.rs @@ -0,0 +1,30 @@ +// 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. + +fn closure_to_loc() { + let mut x = |c| c + 1; + x = |c| c + 1; + //~^ ERROR mismatched types + //~| NOTE no two closures, even if identical, have the same type + //~| HELP consider boxing your closure and/or using it as a trait object +} + +fn closure_from_match() { + let x = match 1usize { + 1 => |c| c + 1, + 2 => |c| c - 1, + _ => |c| c - 1 + }; + //~^^^^^ ERROR match arms have incompatible types + //~| NOTE no two closures, even if identical, have the same type + //~| HELP consider boxing your closure and/or using it as a trait object +} + +fn main() { }