unikernel/duniverse/dune_/test/blackbox-tests/test-cases/gh12057.t

@@ -0,0 +1,56 @@
+Reproduction case for https://github.com/ocaml/dune/issues/12057
+
+A mismatch between an ml file and its mli file usually gives an error message
+mentioning both files. However in dune, it appears that we trigger the mention
+of the .ml twice.
+
+  $ cat > dune-project <<EOF
+  > (lang dune 3.20)
+  > EOF
+
+  $ cat > dune <<EOF
+  > (executable
+  >  (name foo))
+  > EOF
+
+  $ cat > foo.ml <<EOF
+  > let x = 42 ;;
+  > EOF
+
+  $ cat > foo.mli <<EOF
+  > val x : unit
+  > EOF
+
+  $ dune build
+  File "foo.ml", line 1:
+  Error: The implementation foo.ml does not match the interface foo.mli: 
+         Values do not match: val x : int is not included in val x : unit
+         The type int is not compatible with the type unit
+         File "foo.mli", line 1, characters 0-12: Expected declaration
+         File "foo.ml", line 1, characters 4-5: Actual declaration
+  [1]
+
+Compare this with a manual invocation where the error message displays
+correctly.
+
+  $ ocamlc foo.mli
+  $ ocamlc foo.ml
+  File "foo.ml", line 1:
+  Error: The implementation foo.ml does not match the interface foo.mli: 
+         Values do not match: val x : int is not included in val x : unit
+         The type int is not compatible with the type unit
+         File "foo.mli", line 1, characters 0-12: Expected declaration
+         File "foo.ml", line 1, characters 4-5: Actual declaration
+  [2]
+
+The situation in dune is due to -intf-suffix .ml being passed:
+
+  $ ocamlc foo.ml -intf-suffix .ml
+  File "foo.ml", line 1:
+  Error: The implementation foo.ml does not match the interface foo.ml: 
+         Values do not match: val x : int is not included in val x : unit
+         The type int is not compatible with the type unit
+         File "foo.mli", line 1, characters 0-12: Expected declaration
+         File "foo.ml", line 1, characters 4-5: Actual declaration
+  [2]
+