test: alias module regression

Add test to make sure not to mark auto-generated modules as deprecated

Signed-off-by: Marek Kubica <[email protected]>

test/blackbox-tests/test-cases/alias-module-generated.t

@@ -0,0 +1,25 @@
+Test alias module for wrapped libraries that don't have a main module, i.e. the
+wrap module is generated by dune.
+
+  $ cat >dune-project <<EOF
+  > (lang dune 3.5)
+  > EOF
+
+  $ cat >dune <<EOF
+  > (library
+  >  (name foo))
+  > EOF
+  $ touch bar.ml
+
+  $ dune build
+  $ cat _build/default/foo.ml-gen
+  (* generated by dune *)
+
+  (** @canonical Foo.Bar *)
+  module Bar = Foo__Bar
+
+  module Foo = struct end
+  [@@deprecated "this module is shadowed"]
+
+The final `Foo` module should not be marked as deprecated/shadowed, since it
+does not shadow any module.