Print fn signature when there is closure argument type mismatch
Fixes #42143. E0281 is totally replaced by E0631. UI tests are updated accordingly.
This commit is contained in:
Wonwoo Choi
parent
3eb19bf9b1
commit
1bfbfb20a1
14 changed files with 245 additions and 119 deletions
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@ -1139,11 +1139,13 @@ already specify all requirements that will be used for every type parameter.
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"##,
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E0281: r##"
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#### Note: this error code is no longer emitted by the compiler.
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You tried to supply a type which doesn't implement some trait in a location
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which expected that trait. This error typically occurs when working with
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`Fn`-based types. Erroneous code example:
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```compile_fail,E0281
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```compile-fail
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fn foo<F: Fn(usize)>(x: F) { }
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fn main() {
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@ -2086,5 +2088,6 @@ register_diagnostics! {
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E0566, // conflicting representation hints
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E0623, // lifetime mismatch where both parameters are anonymous regions
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E0628, // generators cannot have explicit arguments
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E0631, // type mismatch in closure arguments
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E0637, // "'_" is not a valid lifetime bound
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}
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@ -37,7 +37,7 @@ use rustc::lint::builtin::EXTRA_REQUIREMENT_IN_IMPL;
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use std::fmt;
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use syntax::ast;
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use ty::{self, AdtKind, ToPredicate, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable};
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use ty::error::{ExpectedFound, TypeError};
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use ty::error::ExpectedFound;
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use ty::fast_reject;
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use ty::fold::TypeFolder;
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use ty::subst::Subst;
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@ -711,7 +711,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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}
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}
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OutputTypeParameterMismatch(ref expected_trait_ref, ref actual_trait_ref, ref e) => {
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OutputTypeParameterMismatch(ref expected_trait_ref, ref actual_trait_ref, _) => {
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let expected_trait_ref = self.resolve_type_vars_if_possible(&*expected_trait_ref);
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let actual_trait_ref = self.resolve_type_vars_if_possible(&*actual_trait_ref);
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if actual_trait_ref.self_ty().references_error() {
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@ -722,48 +722,31 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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self.tcx.hir.span_if_local(did)
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});
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if let &TypeError::TupleSize(ref expected_found) = e {
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// Expected `|x| { }`, found `|x, y| { }`
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self.report_arg_count_mismatch(span,
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found_span,
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expected_found.expected,
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expected_found.found,
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expected_trait_ty.is_closure())
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} else if let &TypeError::Sorts(ref expected_found) = e {
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let expected = if let ty::TyTuple(tys, _) = expected_found.expected.sty {
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tys.len()
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} else {
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1
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let self_ty_count =
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match expected_trait_ref.skip_binder().substs.type_at(1).sty {
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ty::TyTuple(ref tys, _) => tys.len(),
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_ => 1,
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};
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let found = if let ty::TyTuple(tys, _) = expected_found.found.sty {
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tys.len()
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} else {
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1
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let arg_ty_count =
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match actual_trait_ref.skip_binder().substs.type_at(1).sty {
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ty::TyTuple(ref tys, _) => tys.len(),
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_ => 1,
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};
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if expected != found {
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// Expected `|| { }`, found `|x, y| { }`
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// Expected `fn(x) -> ()`, found `|| { }`
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self.report_arg_count_mismatch(span,
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found_span,
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expected,
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found,
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expected_trait_ty.is_closure())
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} else {
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self.report_type_argument_mismatch(span,
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found_span,
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expected_trait_ty,
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expected_trait_ref,
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actual_trait_ref,
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e)
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}
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if self_ty_count == arg_ty_count {
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self.report_closure_arg_mismatch(span,
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found_span,
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expected_trait_ref,
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actual_trait_ref)
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} else {
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self.report_type_argument_mismatch(span,
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found_span,
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expected_trait_ty,
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expected_trait_ref,
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actual_trait_ref,
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e)
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// Expected `|| { }`, found `|x, y| { }`
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// Expected `fn(x) -> ()`, found `|| { }`
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self.report_arg_count_mismatch(
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span,
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found_span,
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arg_ty_count,
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self_ty_count,
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expected_trait_ty.is_closure()
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)
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}
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}
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@ -784,31 +767,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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err.emit();
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}
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fn report_type_argument_mismatch(&self,
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span: Span,
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found_span: Option<Span>,
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expected_ty: Ty<'tcx>,
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expected_ref: ty::PolyTraitRef<'tcx>,
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found_ref: ty::PolyTraitRef<'tcx>,
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type_error: &TypeError<'tcx>)
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-> DiagnosticBuilder<'tcx>
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{
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let mut err = struct_span_err!(self.tcx.sess, span, E0281,
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"type mismatch: `{}` implements the trait `{}`, but the trait `{}` is required",
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expected_ty,
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expected_ref,
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found_ref);
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err.span_label(span, format!("{}", type_error));
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if let Some(sp) = found_span {
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err.span_label(span, format!("requires `{}`", found_ref));
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err.span_label(sp, format!("implements `{}`", expected_ref));
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}
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err
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}
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fn report_arg_count_mismatch(&self,
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span: Span,
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found_span: Option<Span>,
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@ -837,6 +795,57 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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}
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err
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}
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fn report_closure_arg_mismatch(&self,
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span: Span,
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found_span: Option<Span>,
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expected_ref: ty::PolyTraitRef<'tcx>,
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found: ty::PolyTraitRef<'tcx>)
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-> DiagnosticBuilder<'tcx>
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{
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fn build_fn_sig_string<'a, 'gcx, 'tcx>(tcx: ty::TyCtxt<'a, 'gcx, 'tcx>,
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trait_ref: &ty::TraitRef<'tcx>) -> String {
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let inputs = trait_ref.substs.type_at(1);
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let sig = if let ty::TyTuple(inputs, _) = inputs.sty {
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tcx.mk_fn_sig(
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inputs.iter().map(|&x| x),
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tcx.mk_infer(ty::TyVar(ty::TyVid { index: 0 })),
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false,
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hir::Unsafety::Normal,
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::syntax::abi::Abi::Rust
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)
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} else {
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tcx.mk_fn_sig(
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::std::iter::once(inputs),
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tcx.mk_infer(ty::TyVar(ty::TyVid { index: 0 })),
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false,
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hir::Unsafety::Normal,
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::syntax::abi::Abi::Rust
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)
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};
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format!("{}", ty::Binder(sig))
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}
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let argument_is_closure = expected_ref.skip_binder().substs.type_at(0).is_closure();
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let mut err = struct_span_err!(self.tcx.sess, span, E0631,
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"type mismatch in {} arguments",
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if argument_is_closure { "closure" } else { "function" });
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let found_str = format!(
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"expected signature of `{}`",
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build_fn_sig_string(self.tcx, found.skip_binder())
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);
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err.span_label(span, found_str);
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let found_span = found_span.unwrap_or(span);
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let expected_str = format!(
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"found signature of `{}`",
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build_fn_sig_string(self.tcx, expected_ref.skip_binder())
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);
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err.span_label(found_span, expected_str);
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err
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}
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}
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impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
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@ -676,6 +676,12 @@ impl<'tcx> fmt::Display for ty::Binder<ty::TraitRef<'tcx>> {
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}
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}
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impl<'tcx> fmt::Display for ty::Binder<ty::FnSig<'tcx>> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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ty::tls::with(|tcx| in_binder(f, tcx, self, tcx.lift(self)))
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}
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}
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impl<'tcx> fmt::Display for ty::Binder<ty::TraitPredicate<'tcx>> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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ty::tls::with(|tcx| in_binder(f, tcx, self, tcx.lift(self)))
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