diff --git a/src/librustc/middle/typeck/check/mod.rs b/src/librustc/middle/typeck/check/mod.rs index f567a880db527..e46b92ae49537 100644 --- a/src/librustc/middle/typeck/check/mod.rs +++ b/src/librustc/middle/typeck/check/mod.rs @@ -863,11 +863,13 @@ pub fn compare_impl_method(tcx: ty::ctxt, if impl_m.fty.sig.inputs.len() != trait_m.fty.sig.inputs.len() { tcx.sess.span_err( impl_m_span, - format!("method `{}` has {} parameter(s) \ - but the trait has {} parameter(s)", - tcx.sess.str_of(trait_m.ident), - impl_m.fty.sig.inputs.len(), - trait_m.fty.sig.inputs.len())); + format!("method `{}` has {} parameter{} \ + but the declaration in trait `{}` has {}", + tcx.sess.str_of(trait_m.ident), + impl_m.fty.sig.inputs.len(), + if impl_m.fty.sig.inputs.len() == 1 { "" } else { "s" }, + ty::item_path_str(tcx, trait_m.def_id), + trait_m.fty.sig.inputs.len())); return; } diff --git a/src/test/compile-fail/trait-impl-different-num-params.rs b/src/test/compile-fail/trait-impl-different-num-params.rs index 940c1b3a237b8..f293644840a1c 100644 --- a/src/test/compile-fail/trait-impl-different-num-params.rs +++ b/src/test/compile-fail/trait-impl-different-num-params.rs @@ -13,7 +13,7 @@ trait foo { } impl foo for int { fn bar(&self) -> int { - //~^ ERROR method `bar` has 0 parameter(s) but the trait has 1 + //~^ ERROR method `bar` has 0 parameters but the declaration in trait `foo::bar` has 1 *self } }