1 files changed, 24 insertions, 0 deletions
diff --git a/tests/ui/const-generics/generic_arg_infer/paren_infer.rs b/tests/ui/const-generics/generic_arg_infer/paren_infer.rs
new file mode 100644
index 00000000000..869683b7056
--- /dev/null
+++ b/tests/ui/const-generics/generic_arg_infer/paren_infer.rs
@@ -0,0 +1,24 @@
+//@ check-pass
+//@ reference: items.generics.const.inferred
+
+struct Foo<const N: usize>;
+
+fn main() {
+    // AST Types preserve parens for pretty printing reasons. This means
+    // that this is parsed as a `TyKind::Paren(TyKind::Infer)`. Generic
+    // arg lowering therefore needs to take into account not just `TyKind::Infer`
+    // but `TyKind::Infer` wrapped in arbitrarily many `TyKind::Paren`.
+    let a: Vec<(_)> = vec![1_u8];
+    let a: Vec<(((((_)))))> = vec![1_u8];
+
+    // AST Exprs similarly preserve parens for pretty printing reasons.
+    #[rustfmt::skip]
+    let b: [u8; (_)] = [1; (((((_)))))];
+    let b: [u8; 2] = b;
+
+    // This is the same case as AST types as the parser doesn't distinguish between const
+    // and type args when they share syntax
+    let c: Foo<_> = Foo::<1>;
+    let c: Foo<(_)> = Foo::<1>;
+    let c: Foo<(((_)))> = Foo::<1>;
+}