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diff --git a/tests/ui/or-patterns/nested-undelimited-precedence.rs b/tests/ui/or-patterns/nested-undelimited-precedence.rs
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+++ b/tests/ui/or-patterns/nested-undelimited-precedence.rs
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+// This test tests the precedence of `|` (or-patterns) undelimited nested patterns. In particular,
+// we want to reserve the syntactic space of a pattern followed by a type annotation for possible
+// future type ascription, so we need to make sure that any time a pattern is followed by type
+// annotation (for now), the pattern is not a top-level or-pattern. However, there are also a few
+// types of patterns that allow undelimited subpatterns that could cause the same ambiguity.
+// Currently, those should be impossible due to precedence rule. This test enforces that.
+
+enum E {
+    A,
+    B,
+}
+
+fn foo() {
+    use E::*;
+
+    // ok
+    let b @ (A | B): E = A;
+
+    let b @ A | B: E = A; //~ERROR `b` is not bound in all patterns
+    //~^ ERROR top-level or-patterns are not allowed
+}
+
+enum F {
+    A(usize),
+    B(usize),
+}
+
+fn bar() {
+    use F::*;
+
+    // ok
+    let (A(x) | B(x)): F = A(3);
+
+    let &A(_) | B(_): F = A(3); //~ERROR mismatched types
+    //~^ ERROR top-level or-patterns are not allowed
+    let &&A(_) | B(_): F = A(3); //~ERROR mismatched types
+    //~^ ERROR top-level or-patterns are not allowed
+    let &mut A(_) | B(_): F = A(3); //~ERROR mismatched types
+    //~^ ERROR top-level or-patterns are not allowed
+    let &&mut A(_) | B(_): F = A(3); //~ERROR mismatched types
+    //~^ ERROR top-level or-patterns are not allowed
+}
+
+fn main() {}