fix(compiler): Ensure reprovided types unify (#2051)

compiler/src/typed/typemod.re

@@ -674,6 +674,15 @@ let rec type_module = (~toplevel=false, anchor, env, statements) => {
             | Some(_) => failwith("Impossible: invalid alias")
             | None => Ident.create(name.txt)
             };
+          let type_ =
+            switch (type_path) {
+            | PExternal(_) => {
+                ...type_,
+                type_manifest:
+                  Some(Ctype.newconstr(type_path, type_.type_params)),
+              }
+            | PIdent(_) => type_
+            };
           ([TSigType(id, type_, TRecNot), ...sigs], stmts);
         | PProvideException({name: {txt: IdentName(name)}, alias, loc}) =>
           let ext = Typetexp.find_exception(env, loc, IdentName(name));

compiler/test/input/reprovideTypeUnifyA.gr

@@ -0,0 +1,5 @@
+module ReprovideTypeUnifyA
+
+from "./reprovideTypeUnifyB" include ReprovideTypeUnifyB
+use ReprovideTypeUnifyB.{ type T, a }
+print(a == { x: 1, })

compiler/test/input/reprovideTypeUnifyB.gr

@@ -0,0 +1,6 @@
+module ReprovideTypeUnifyB
+
+from "./reprovideTypeUnifyC" include ReprovideTypeUnifyC
+use ReprovideTypeUnifyC.{ type T }
+let a = { x: 1, }
+provide { type T, a }

compiler/test/input/reprovideTypeUnifyC.gr

@@ -0,0 +1,5 @@
+module ReprovideTypeUnifyC
+
+provide record T {
+  x: Number,
+}

compiler/test/suites/provides.re

@@ -13,6 +13,7 @@ describe("provides", ({test, testSkip}) => {
     );
   let assertCompileError = makeCompileErrorRunner(test);
   let assertRun = makeRunner(test_or_skip);
+  let assertFileRun = makeFileRunner(test_or_skip);
   let assertRunError = makeErrorRunner(test_or_skip);
   let assertHasWasmExport = (name, prog, expectedExports) => {
     test(
@@ -249,4 +250,9 @@ describe("provides", ({test, testSkip}) => {
     "module Test; enum T { A }; provide let a = A; provide { type T }",
     [("GRAIN$EXPORT$a", Binaryen.Export.external_global)],
   );
+  assertFileRun(
+    "issue_1886_type_reprovided_unify",
+    "reprovideTypeUnifyA",
+    "true\n",
+  );
 });