fix(compiler): Allow providing values of types provided later (#1897)

Author: alex-snezhko

compiler/src/typed/typed_well_formedness.re

@@ -91,6 +91,22 @@ let ensure_no_escaped_types = (signature, statements) => {
       Ident.Set.empty,
       statements,
     );
+  // Remove types provided after initial type definition (with `provide { type X }` statement)
+  let private_idents =
+    List.fold_left(
+      (private_idents, sig_) => {
+        switch (sig_) {
+        | Types.TSigType(id, _, _) =>
+          switch (Ident.Set.find_first_opt(Ident.equal(id), private_idents)) {
+          | Some(to_remove) => Ident.Set.remove(to_remove, private_idents)
+          | None => private_idents
+          }
+        | _ => private_idents
+        }
+      },
+      private_idents,
+      signature,
+    );
   let ctx_loc = ctx => {
     switch (ctx) {
     | Value(loc)

compiler/test/suites/provides.re

@@ -189,4 +189,24 @@ describe("provides", ({test, testSkip}) => {
       ("GRAIN$EXPORT$y", Binaryen.Export.external_global),
     ],
   );
+  assertHasWasmExport(
+    "issue_1884_type_provided_later1",
+    "module Test; enum T { A }; let a = A; provide { type T }; provide { a }",
+    [("GRAIN$EXPORT$a", Binaryen.Export.external_global)],
+  );
+  assertHasWasmExport(
+    "issue_1884_type_provided_later2",
+    "module Test; enum T { A }; let a = A; provide { a, type T }",
+    [("GRAIN$EXPORT$a", Binaryen.Export.external_global)],
+  );
+  assertHasWasmExport(
+    "issue_1884_type_provided_later3",
+    "module Test; enum T { A }; let a = A; provide { a }; provide { type T }",
+    [("GRAIN$EXPORT$a", Binaryen.Export.external_global)],
+  );
+  assertHasWasmExport(
+    "issue_1884_type_provided_later4",
+    "module Test; enum T { A }; provide let a = A; provide { type T }",
+    [("GRAIN$EXPORT$a", Binaryen.Export.external_global)],
+  );
 });