1 files changed, 64 insertions, 0 deletions
diff --git a/test-suite/bugs/closed/5180.v b/test-suite/bugs/closed/5180.v
new file mode 100644
index 00000000..261092ee
--- /dev/null
+++ b/test-suite/bugs/closed/5180.v
@@ -0,0 +1,64 @@
+Universes a b c ω ω'.
+Definition Typeω := Type@{ω}.
+Definition Type2 : Typeω := Type@{c}.
+Definition Type1 : Type2 := Type@{b}.
+Definition Type0 : Type1 := Type@{a}.
+
+Set Universe Polymorphism.
+Set Printing Universes.
+
+Definition Typei' (n : nat)
+  := match n return Type@{ω'} with
+     | 0 => Type0
+     | 1 => Type1
+     | 2 => Type2
+     | _ => Typeω
+     end.
+Definition TypeOfTypei' {n} (x : Typei' n) : Type@{ω'}
+  := match n return Typei' n -> Type@{ω'} with
+     | 0 | 1 | 2 | _ => fun x => x
+     end x.
+Definition Typei (n : nat) : Typei' (S n)
+  := match n return Typei' (S n) with
+     | 0 => Type0
+     | 1 => Type1
+     | _ => Type2
+     end.
+Definition TypeOfTypei {n} (x : TypeOfTypei' (Typei n)) : Type@{ω'}
+  := match n return TypeOfTypei' (Typei n) -> Type@{ω'} with
+     | 0 | 1 | _ => fun x => x
+     end x.
+Check Typei 0 : Typei 1.
+Check Typei 1 : Typei 2.
+
+Definition lift' {n} : TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n))
+  := match n return TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n)) with
+     | 0 | 1 | 2 | _ => fun x => (x : Type)
+     end.
+Definition lift'' {n} : TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n))
+  := match n return TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n)) with
+     | 0 | 1 | 2 | _ => fun x => x
+     end. (* The command has indeed failed with message:
+In environment
+n : nat
+x : TypeOfTypei' (Typei 0)
+The term "x" has type "TypeOfTypei' (Typei 0)" while it is expected to have type
+ "TypeOfTypei' (Typei 1)" (universe inconsistency: Cannot enforce b = a because  a < b).
+ *)
+Check (fun x : TypeOfTypei' (Typei 0) => TypeOfTypei' (Typei 1)).
+
+Definition lift''' {n} : TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n)).
+  refine match n return TypeOfTypei' (Typei n) -> TypeOfTypei' (Typei (S n))  with
+         | 0 | 1 | 2 | _ => fun x => _
+         end.
+  exact x.
+  Undo.
+  (* The command has indeed failed with message:
+In environment
+n : nat
+x : TypeOfTypei' (Typei 0)
+The term "x" has type "TypeOfTypei' (Typei 0)" while it is expected to have type
+ "TypeOfTypei' (Typei 1)" (universe inconsistency: Cannot enforce b = a because  a < b).
+ *)
+  all:compute in *.
+  all:exact x.
+\ No newline at end of file