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Point out custom Fn-family trait impl

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This commit is contained in:
Michael Goulet 2022-07-13 05:39:01 +00:00
parent ddb7003b79
commit d25abdc0c5
3 changed files with 114 additions and 53 deletions
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8
compiler/rustc_middle/src/ty/closure.rs
View File

@ -128,6 +128,14 @@ impl<'tcx> ClosureKind {
None
}
}
pub fn to_def_id(&self, tcx: TyCtxt<'_>) -> DefId {
match self {
ClosureKind::Fn => tcx.lang_items().fn_once_trait().unwrap(),
ClosureKind::FnMut => tcx.lang_items().fn_mut_trait().unwrap(),
ClosureKind::FnOnce => tcx.lang_items().fn_trait().unwrap(),
}
}
}
/// A composite describing a `Place` that is captured by a closure.

143
compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
View File

@ -21,6 +21,7 @@ use rustc_hir::def_id::DefId;
use rustc_hir::{ExprKind, Node, QPath};
use rustc_index::vec::IndexVec;
use rustc_infer::infer::error_reporting::{FailureCode, ObligationCauseExt};
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::InferOk;
use rustc_infer::infer::TypeTrace;
use rustc_middle::ty::adjustment::AllowTwoPhase;
@ -29,7 +30,9 @@ use rustc_middle::ty::{self, DefIdTree, IsSuggestable, Ty};
use rustc_session::Session;
use rustc_span::symbol::Ident;
use rustc_span::{self, Span};
use rustc_trait_selection::traits::{self, ObligationCauseCode, StatementAsExpression};
use rustc_trait_selection::traits::{
self, ObligationCauseCode, SelectionContext, StatementAsExpression,
};
use std::iter;
use std::slice;
@ -393,41 +396,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
if !call_appears_satisfied {
// Next, let's construct the error
let (error_span, full_call_span, ctor_of) = match &call_expr.kind {
hir::ExprKind::Call(
hir::Expr {
span,
kind:
hir::ExprKind::Path(hir::QPath::Resolved(
_,
hir::Path { res: Res::Def(DefKind::Ctor(of, _), _), .. },
)),
..
},
_,
) => (call_span, *span, Some(of)),
hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None),
hir::ExprKind::MethodCall(path_segment, _, span) => {
let ident_span = path_segment.ident.span;
let ident_span = if let Some(args) = path_segment.args {
ident_span.with_hi(args.span_ext.hi())
} else {
ident_span
};
(
*span, ident_span, None, // methods are never ctors
)
}
k => span_bug!(call_span, "checking argument types on a non-call: `{:?}`", k),
};
let args_span = error_span.trim_start(full_call_span).unwrap_or(error_span);
let call_name = match ctor_of {
Some(CtorOf::Struct) => "struct",
Some(CtorOf::Variant) => "enum variant",
None => "function",
};
let compatibility_diagonal = IndexVec::from_raw(compatibility_diagonal);
let provided_args = IndexVec::from_iter(provided_args.iter().take(if c_variadic {
minimum_input_count
@ -451,13 +419,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
compatibility_diagonal,
formal_and_expected_inputs,
provided_args,
full_call_span,
error_span,
args_span,
call_name,
c_variadic,
err_code,
fn_def_id,
call_span,
call_expr,
);
}
@ -468,15 +433,47 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
provided_args: IndexVec<ProvidedIdx, &'tcx hir::Expr<'tcx>>,
full_call_span: Span,
error_span: Span,
args_span: Span,
call_name: &str,
c_variadic: bool,
err_code: &str,
fn_def_id: Option<DefId>,
call_span: Span,
call_expr: &hir::Expr<'tcx>,
) {
// Next, let's construct the error
let (error_span, full_call_span, ctor_of) = match &call_expr.kind {
hir::ExprKind::Call(
hir::Expr {
span,
kind:
hir::ExprKind::Path(hir::QPath::Resolved(
_,
hir::Path { res: Res::Def(DefKind::Ctor(of, _), _), .. },
)),
..
},
_,
) => (call_span, *span, Some(of)),
hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None),
hir::ExprKind::MethodCall(path_segment, _, span) => {
let ident_span = path_segment.ident.span;
let ident_span = if let Some(args) = path_segment.args {
ident_span.with_hi(args.span_ext.hi())
} else {
ident_span
};
(
*span, ident_span, None, // methods are never ctors
)
}
k => span_bug!(call_span, "checking argument types on a non-call: `{:?}`", k),
};
let args_span = error_span.trim_start(full_call_span).unwrap_or(error_span);
let call_name = match ctor_of {
Some(CtorOf::Struct) => "struct",
Some(CtorOf::Variant) => "enum variant",
None => "function",
};
// Don't print if it has error types or is just plain `_`
fn has_error_or_infer<'tcx>(tys: impl IntoIterator<Item = Ty<'tcx>>) -> bool {
tys.into_iter().any(|ty| ty.references_error() || ty.is_ty_var())
@ -1818,17 +1815,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fn label_fn_like(
&self,
err: &mut rustc_errors::DiagnosticBuilder<'tcx, rustc_errors::ErrorGuaranteed>,
def_id: Option<DefId>,
callable_def_id: Option<DefId>,
callee_ty: Option<Ty<'tcx>>,
) {
let Some(mut def_id) = def_id else {
let Some(mut def_id) = callable_def_id else {
return;
};
if let Some(assoc_item) = self.tcx.opt_associated_item(def_id)
&& let trait_def_id = assoc_item.trait_item_def_id.unwrap_or_else(|| self.tcx.parent(def_id))
// Possibly points at either impl or trait item, so try to get it
// to point to trait item, then get the parent.
// This parent might be an impl in the case of an inherent function,
// but the next check will fail.
&& let maybe_trait_item_def_id = assoc_item.trait_item_def_id.unwrap_or(def_id)
&& let maybe_trait_def_id = self.tcx.parent(maybe_trait_item_def_id)
// Just an easy way to check "trait_def_id == Fn/FnMut/FnOnce"
&& ty::ClosureKind::from_def_id(self.tcx, trait_def_id).is_some()
&& let Some(call_kind) = ty::ClosureKind::from_def_id(self.tcx, maybe_trait_def_id)
&& let Some(callee_ty) = callee_ty
{
let callee_ty = callee_ty.peel_refs();
@ -1853,7 +1855,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
std::iter::zip(instantiated.predicates, instantiated.spans)
{
if let ty::PredicateKind::Trait(pred) = predicate.kind().skip_binder()
&& pred.self_ty() == callee_ty
&& pred.self_ty().peel_refs() == callee_ty
&& ty::ClosureKind::from_def_id(self.tcx, pred.def_id()).is_some()
{
err.span_note(span, "callable defined here");
@ -1862,11 +1864,46 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
}
ty::Opaque(new_def_id, _) | ty::Closure(new_def_id, _) | ty::FnDef(new_def_id, _) => {
ty::Opaque(new_def_id, _)
| ty::Closure(new_def_id, _)
| ty::FnDef(new_def_id, _) => {
def_id = new_def_id;
}
_ => {
return;
// Look for a user-provided impl of a `Fn` trait, and point to it.
let new_def_id = self.probe(|_| {
let trait_ref = ty::TraitRef::new(
call_kind.to_def_id(self.tcx),
self.tcx.mk_substs([
ty::GenericArg::from(callee_ty),
self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::MiscVariable,
span: rustc_span::DUMMY_SP,
})
.into(),
].into_iter()),
);
let obligation = traits::Obligation::new(
traits::ObligationCause::dummy(),
self.param_env,
ty::Binder::dummy(ty::TraitPredicate {
trait_ref,
constness: ty::BoundConstness::NotConst,
polarity: ty::ImplPolarity::Positive,
}),
);
match SelectionContext::new(&self).select(&obligation) {
Ok(Some(traits::ImplSource::UserDefined(impl_source))) => {
Some(impl_source.impl_def_id)
}
_ => None
}
});
if let Some(new_def_id) = new_def_id {
def_id = new_def_id;
} else {
return;
}
}
}
}
@ -1888,8 +1925,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let def_kind = self.tcx.def_kind(def_id);
err.span_note(spans, &format!("{} defined here", def_kind.descr(def_id)));
} else if let def_kind @ (DefKind::Closure | DefKind::OpaqueTy) = self.tcx.def_kind(def_id)
{
} else {
let def_kind = self.tcx.def_kind(def_id);
err.span_note(
self.tcx.def_span(def_id),
&format!("{} defined here", def_kind.descr(def_id)),

16
src/test/ui/mismatched_types/overloaded-calls-bad.stderr
View File

@ -5,6 +5,12 @@ LL | let ans = s("what");
| - ^^^^^^ expected `isize`, found `&str`
| |
| arguments to this function are incorrect
|
note: implementation defined here
--> $DIR/overloaded-calls-bad.rs:10:1
|
LL | impl FnMut<(isize,)> for S {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0057]: this function takes 1 argument but 0 arguments were supplied
--> $DIR/overloaded-calls-bad.rs:29:15
@ -12,6 +18,11 @@ error[E0057]: this function takes 1 argument but 0 arguments were supplied
LL | let ans = s();
| ^-- an argument of type `isize` is missing
|
note: implementation defined here
--> $DIR/overloaded-calls-bad.rs:10:1
|
LL | impl FnMut<(isize,)> for S {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: provide the argument
|
LL | let ans = s(/* isize */);
@ -25,6 +36,11 @@ LL | let ans = s("burma", "shave");
| |
| expected `isize`, found `&str`
|
note: implementation defined here
--> $DIR/overloaded-calls-bad.rs:10:1
|
LL | impl FnMut<(isize,)> for S {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: remove the extra argument
|
LL | let ans = s(/* isize */);