mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Limit displaying relevant trait impls to 4

Browse Source
This commit is contained in:
Florian Hahn 2015-11-28 11:41:52 +01:00
parent 335298e7b6
commit 2c52cb424a
1 changed files with 34 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
src/librustc/middle/traits/error_reporting.rs
View File

@ -30,6 +30,7 @@ use middle::ty::{self, ToPredicate, HasTypeFlags, ToPolyTraitRef, TraitRef, Ty};
use middle::ty::fold::TypeFoldable;
use util::nodemap::{FnvHashMap, FnvHashSet};
use std::cmp;
use std::fmt;
use syntax::attr::{AttributeMethods, AttrMetaMethods};
use syntax::codemap::Span;
@ -225,38 +226,49 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
"the trait `{}` is not implemented for the type `{}`",
trait_ref, trait_ref.self_ty());
let mut counter = 1;
infcx.tcx.sess.fileline_help(
obligation.cause.span,
"the following implementations were found:");
infcx.tcx.lookup_trait_def(trait_ref.def_id()).for_each_relevant_impl(
infcx.tcx,
trait_ref.self_ty(),
|impl_def_id| {
match infcx.tcx.impl_trait_ref(impl_def_id) {
Some(ref imp) => {
infcx.tcx.sess.fileline_help(
obligation.cause.span,
&format!("implementation {}: `{}`", counter, imp));
counter += 1;
},
None => (),
}
}
);
// Check if it has a custom "#[rustc_on_unimplemented]"
// error message, report with that message if it does
let custom_note = report_on_unimplemented(infcx, &trait_ref.0,
obligation.cause.span);
if let Some(s) = custom_note {
err.fileline_note(obligation.cause.span, &s);
} else {
let mut impl_candidates = Vec::new();
infcx.tcx.lookup_trait_def(trait_ref.def_id())
.for_each_relevant_impl(
infcx.tcx,
trait_ref.self_ty(),
|impl_def_id| {
match infcx.tcx.impl_trait_ref(impl_def_id) {
Some(ref imp) => {
impl_candidates.push(format!(" {}", imp));
},
None => (),
}
}
);
if impl_candidates.len() > 0 {
err.fileline_help(
obligation.cause.span,
&format!("the following implementations were found:"));
let end = cmp::min(4, impl_candidates.len());
for candidate in &impl_candidates[0..end] {
err.fileline_help(obligation.cause.span,
candidate);
}
if impl_candidates.len() > 4 {
err.fileline_help(obligation.cause.span,
&format!("and {} others",
impl_candidates.len()-4));
}
}
}
note_obligation_cause(infcx, &mut err, obligation);
err.emit();
}
}
},
ty::Predicate::Equate(ref predicate) => {
let predicate = infcx.resolve_type_vars_if_possible(predicate);
let err = infcx.equality_predicate(obligation.cause.span,