Support for overriding upstream types in eqwalizer_types.erl

Summary: Use module `eqwalizer_types` to override any upstream type, similar to how `eqwalizer_specs` is used.

Reviewed By: ilya-klyuchnikov

Differential Revision: D65831604

fbshipit-source-id: 4e6f1c30412d6e5f991c91e001cd81f395cc872f

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/ast/stub/CustomTypes.scala

@@ -0,0 +1,36 @@
+/* Copyright (c) Meta Platforms, Inc. and affiliates. All rights reserved.
+ *
+ * This source code is licensed under the Apache 2.0 license found in
+ * the LICENSE file in the root directory of this source tree.
+ */
+
+package com.whatsapp.eqwalizer.ast.stub
+
+import com.whatsapp.eqwalizer.ast.Forms.TypeDecl
+import com.whatsapp.eqwalizer.ast.Id
+
+private object CustomTypes {
+  private lazy val customTypes: Map[String, Map[Id, TypeDecl]] =
+    Db.getModuleStub("eqwalizer_types") match {
+      case Some(stub) =>
+        stub.types.toList
+          .map { case (id, ty) =>
+            val Array(module, tyName) = id.name.split(":")
+            val id1 = Id(tyName, id.arity)
+            val ty1 = ty.copy(id = id1)(ty.pos)
+            (module, id1) -> ty1
+          }
+          .groupBy { case ((module, _), _) => module }
+          .view
+          .mapValues(_.map { case ((_, id), ty) => id -> ty }.toMap)
+          .toMap
+      case None =>
+        Map.empty
+    }
+
+  def getType(module: String, id: Id): Option[TypeDecl] =
+    for {
+      types <- customTypes.get(module)
+      ty <- types.get(id)
+    } yield ty
+}

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/ast/stub/DbApi.scala

@@ -42,8 +42,11 @@ object DbApi {
   def getImports(module: String): Option[Map[Id, String]] =
     Db.getModuleStub(module).map(_.imports)
 
-  def getType(module: String, id: Id): Option[TypeDecl] =
-    Db.getModuleStub(module).flatMap(_.types.get(id))
+  def getType(module: String, id: Id): Option[TypeDecl] = {
+    CustomTypes.getType(module, id).orElse {
+      Db.getModuleStub(module).flatMap(_.types.get(id))
+    }
+  }
 
   def getPrivateOpaque(module: String, id: Id): Option[TypeDecl] =
     Db.getModuleStub(module).flatMap(_.privateOpaques.get(id))