Allow mutable return reference on signatures with any lifetime in argument
diff --git a/syntax/check.rs b/syntax/check.rs
index 807847c..591e53d 100644
--- a/syntax/check.rs
+++ b/syntax/check.rs
@@ -1,5 +1,6 @@
use crate::syntax::atom::Atom::{self, *};
use crate::syntax::report::Errors;
+use crate::syntax::visit::{self, Visit};
use crate::syntax::{
error, ident, trivial, Api, Array, Enum, ExternFn, ExternType, Impl, Lang, NamedType, Ptr,
Receiver, Ref, Signature, SliceRef, Struct, Trait, Ty1, Type, TypeAlias, Types,
@@ -518,20 +519,45 @@
_ => return,
}
- if let Some(r) = &efn.receiver {
- if r.mutable {
+ if let Some(receiver) = &efn.receiver {
+ if receiver.mutable {
+ return;
+ }
+ let resolve = cx.types.resolve(&receiver.ty);
+ if !resolve.generics.lifetimes.is_empty() {
return;
}
}
- for arg in &efn.args {
- if let Type::Ref(ty) = &arg.ty {
- if ty.mutable {
- return;
- }
+ struct FindLifetimeMut<'a> {
+ cx: &'a Check<'a>,
+ found: bool,
+ }
+
+ impl<'t, 'a> Visit<'t> for FindLifetimeMut<'a> {
+ fn visit_type(&mut self, ty: &'t Type) {
+ self.found |= match ty {
+ Type::Ref(ty) => ty.mutable,
+ Type::Ident(ident) => {
+ let resolve = self.cx.types.resolve(ident);
+ !resolve.generics.lifetimes.is_empty()
+ }
+ _ => false,
+ };
+ visit::visit_type(self, ty);
}
}
+ let mut visitor = FindLifetimeMut { cx, found: false };
+
+ for arg in &efn.args {
+ visitor.visit_type(&arg.ty);
+ }
+
+ if visitor.found {
+ return;
+ }
+
cx.error(
efn,
"&mut return type is not allowed unless there is a &mut argument",
diff --git a/tests/ui/mut_return.stderr b/tests/ui/mut_return.stderr
index 76ac7db..5845eb8 100644
--- a/tests/ui/mut_return.stderr
+++ b/tests/ui/mut_return.stderr
@@ -3,15 +3,3 @@
|
10 | fn f(t: &Thing) -> Pin<&mut CxxString>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: &mut return type is not allowed unless there is a &mut argument
- --> $DIR/mut_return.rs:12:9
- |
-12 | fn h(t: Box<Mut>) -> Pin<&mut CxxString>;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: &mut return type is not allowed unless there is a &mut argument
- --> $DIR/mut_return.rs:13:9
- |
-13 | fn i<'a>(t: Box<Mut<'a>>) -> Pin<&'a mut CxxString>;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^