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Add basic checks for well-formedness of fn/fn_mut lang items

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This commit is contained in:
Fabian Wolff 2021-06-12 12:48:04 +02:00
parent a0648eab36
commit 4337089098
6 changed files with 161 additions and 6 deletions
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18
compiler/rustc_typeck/src/check/callee.rs
View file

@ -246,12 +246,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
if borrow {
// Check for &self vs &mut self in the method signature. Since this is either
// the Fn or FnMut trait, it should be one of those.
let (region, mutbl) =
if let ty::Ref(r, _, mutbl) = method.sig.inputs()[0].kind() {
(r, mutbl)
} else {
span_bug!(call_expr.span, "input to call/call_mut is not a ref?");
};
let (region, mutbl) = if let ty::Ref(r, _, mutbl) =
method.sig.inputs()[0].kind()
{
(r, mutbl)
} else {
// The `fn`/`fn_mut` lang item is ill-formed, which should have
// caused an error elsewhere.
self.tcx
.sess
.delay_span_bug(call_expr.span, "input to call/call_mut is not a ref?");
return None;
};
let mutbl = match mutbl {
hir::Mutability::Not => AutoBorrowMutability::Not,

34
compiler/rustc_typeck/src/check/wfcheck.rs
View file

@ -200,6 +200,40 @@ pub fn check_trait_item(tcx: TyCtxt<'_>, def_id: LocalDefId) {
};
check_object_unsafe_self_trait_by_name(tcx, &trait_item);
check_associated_item(tcx, trait_item.hir_id(), span, method_sig);
let encl_trait_hir_id = tcx.hir().get_parent_item(hir_id);
let encl_trait = tcx.hir().expect_item(encl_trait_hir_id);
if [tcx.lang_items().fn_trait(), tcx.lang_items().fn_mut_trait()]
.contains(&Some(encl_trait.def_id.to_def_id()))
&& trait_item.ident.name.to_ident_string() == "call"
{
// We are looking at the `call` function of the `fn` or `fn_mut` lang item.
// Do some rudimentary sanity checking to avoid an ICE later (issue #83471).
if let Some(method_sig @ hir::FnSig { decl, .. }) = method_sig {
if let &[self_ty, _] = &decl.inputs {
if !matches!(self_ty.kind, hir::TyKind::Rptr(_, _)) {
tcx.sess.struct_span_err(
self_ty.span,
"first argument of `call` in `fn`/`fn_mut` lang item must be a reference",
).emit();
}
} else {
tcx.sess
.struct_span_err(
method_sig.span,
"`call` function in `fn`/`fn_mut` lang item takes exactly two arguments",
)
.emit();
}
} else {
tcx.sess
.struct_span_err(
trait_item.span,
"`call` trait item in `fn`/`fn_mut` lang item must be a function",
)
.emit();
}
}
}
fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool {