Add fallback for return type
@@ -149,9 +149,9 @@ fn signature_help_for_call(
}
// APITs (argument position `impl Trait`s) are inferred as {unknown} as the user is
// in the middle of entering call arguments.
- // In that case, fall back to render definition of the argument.
+ // In that case, fall back to render definitions of the respective parameters.
// This is overly conservative: we do not substitute known type vars
- // (see FIXME in tests::impl_trait).
+ // (see FIXME in tests::impl_trait) and falling back on any unknowns.
match (ty.contains_unknown(), fn_params.as_deref()) {
(true, Some(fn_params)) => format_to!(buf, "{}", fn_params[idx].ty().display(db)),
_ => format_to!(buf, "{}", ty.display(db)),
@@ -161,12 +161,17 @@ fn signature_help_for_call(
}
res.signature.push(')');
- match callable.kind() {
- hir::CallableKind::Function(_) | hir::CallableKind::Closure => {
- let ret_type = callable.return_type();
+ let mut render = |ret_type: hir::Type| {
if !ret_type.is_unit() {
format_to!(res.signature, " -> {}", ret_type.display(db));
}
+ };
+ match callable.kind() {
+ hir::CallableKind::Function(func) if callable.return_type().contains_unknown() => {
+ render(func.ret_type(db))
+ }
+ hir::CallableKind::Function(_) | hir::CallableKind::Closure => {
+ render(callable.return_type())
}
hir::CallableKind::TupleStruct(_) | hir::CallableKind::TupleEnumVariant(_) => {}
}
@@ -444,7 +449,7 @@ fn foo<T>() -> T where T: Copy + Display {}
fn bar() { foo($0); }
"#,
expect![[r#"
- fn foo() -> {unknown}
+ fn foo() -> T
"#]],
);
}
