1 files changed, 25 insertions, 0 deletions
diff --git a/test-suite/bugs/opened/3278.v b/test-suite/bugs/opened/3278.v
new file mode 100644
index 00000000..ced535af
--- /dev/null
+++ b/test-suite/bugs/opened/3278.v
@@ -0,0 +1,25 @@
+Module a.
+  Check let x' := _ in
+             $(exact x')$.
+
+  Notation foo x := (let x' := x in $(exact x')$).
+
+  Fail Check foo _. (* Error:
+Cannot infer an internal placeholder of type "Type" in environment:
+
+x' := ?42 : ?41
+. *)
+End a.
+
+Module b.
+  Notation foo x := (let x' := x in let y := ($(exact I)$ : True) in I).
+  Notation bar x := (let x' := x in let y := (I : True) in I).
+
+  Check let x' := _ in $(exact I)$. (* let x' := ?5 in I *)
+  Check bar _. (* let x' := ?9 in let y := I in I *)
+  Fail Check foo _. (* Error:
+Cannot infer an internal placeholder of type "Type" in environment:
+
+x' := ?42 : ?41
+. *)
+End b.