Re-add support for local Flow bindings (TypeAlias, OpaqueTypeAlias and Interface) (#7900)

packages/babel-traverse/src/scope/index.js

@@ -68,9 +68,6 @@ const collectorVisitor = {
       return;
     }
 
-    // TODO(amasad): remove support for flow as bindings (See warning below).
-    //if (path.isFlow()) return;
-
     // we've ran into a declaration!
     const parent =
       path.scope.getFunctionParent() || path.scope.getProgramParent();
@@ -468,8 +465,6 @@ export default class Scope {
   }
 
   registerDeclaration(path: NodePath) {
-    if (path.isFlow()) return;
-
     if (path.isLabeledStatement()) {
       this.registerLabel(path);
     } else if (path.isFunctionDeclaration()) {

packages/babel-traverse/test/scope.js

@@ -72,16 +72,80 @@ describe("scope", function() {
       expect(
         getPath("declare var foo;", { plugins: ["flow"] }).scope.getBinding(
           "foo",
-        ),
-      ).toBeUndefined();
+        ).path.type,
+      ).toBe("DeclareVariable");
     });
 
     it("declare function", function() {
       expect(
         getPath("declare function foo(): void;", {
           plugins: ["flow"],
-        }).scope.getBinding("foo"),
-      ).toBeUndefined();
+        }).scope.getBinding("foo").path.type,
+      ).toBe("DeclareFunction");
+    });
+
+    it("declare module", function() {
+      expect(
+        getPath("declare module foo {};", {
+          plugins: ["flow"],
+        }).scope.getBinding("foo").path.type,
+      ).toBe("DeclareModule");
+    });
+
+    it("declare type alias", function() {
+      expect(
+        getPath("declare type foo = string;", {
+          plugins: ["flow"],
+        }).scope.getBinding("foo").path.type,
+      ).toBe("DeclareTypeAlias");
+    });
+
+    it("declare opaque type", function() {
+      expect(
+        getPath("declare opaque type foo;", {
+          plugins: ["flow"],
+        }).scope.getBinding("foo").path.type,
+      ).toBe("DeclareOpaqueType");
+    });
+
+    it("declare interface", function() {
+      expect(
+        getPath("declare interface Foo {};", {
+          plugins: ["flow"],
+        }).scope.getBinding("Foo").path.type,
+      ).toBe("DeclareInterface");
+    });
+
+    it("type alias", function() {
+      expect(
+        getPath("type foo = string;", {
+          plugins: ["flow"],
+        }).scope.getBinding("foo").path.type,
+      ).toBe("TypeAlias");
+    });
+
+    it("opaque type alias", function() {
+      expect(
+        getPath("opaque type foo = string;", {
+          plugins: ["flow"],
+        }).scope.getBinding("foo").path.type,
+      ).toBe("OpaqueType");
+    });
+
+    it("interface", function() {
+      expect(
+        getPath("interface Foo {};", {
+          plugins: ["flow"],
+        }).scope.getBinding("Foo").path.type,
+      ).toBe("InterfaceDeclaration");
+    });
+
+    it("import type", function() {
+      expect(
+        getPath("import type {Foo} from 'foo';", {
+          plugins: ["flow"],
+        }).scope.getBinding("Foo").path.type,
+      ).toBe("ImportSpecifier");
     });
 
     it("variable constantness", function() {

packages/babel-types/src/retrievers/getBindingIdentifiers.js

@@ -74,6 +74,9 @@ getBindingIdentifiers.keys = {
   DeclareFunction: ["id"],
   DeclareModule: ["id"],
   DeclareVariable: ["id"],
+  DeclareInterface: ["id"],
+  DeclareTypeAlias: ["id"],
+  DeclareOpaqueType: ["id"],
   InterfaceDeclaration: ["id"],
   TypeAlias: ["id"],
   OpaqueType: ["id"],