From b5fb53b718d15e95252197b5f30787ca807d069a Mon Sep 17 00:00:00 2001
From: Andres Suarez <zertosh@gmail.com>
Date: Thu, 23 Mar 2017 12:49:19 -0400
Subject: [PATCH] Fix type param and interface declaration scoping (#449)

---
 index.js               | 40 +++++++++++++++------------
 test/non-regression.js | 63 ++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 83 insertions(+), 20 deletions(-)

diff --git a/index.js b/index.js
index 39b6142a..8d05f794 100644
--- a/index.js
+++ b/index.js
@@ -180,18 +180,6 @@ function monkeypatch() {
     }
   }
 
-  function visitTypeParameters(typeParameters) {
-    var params = typeParameters.params;
-
-    // visit bounds on polymorphpic types, eg; `Foo` in `fn<T: Foo>(a: T): T`
-    for (var i = 0; i < params.length; i++) {
-      var param = params[i];
-      if (param.typeAnnotation) {
-        visitTypeAnnotation.call(this, param.typeAnnotation);
-      }
-    }
-  }
-
   function checkIdentifierOrVisit(node) {
     if (node.typeAnnotation) {
       visitTypeAnnotation.call(this, node.typeAnnotation);
@@ -209,6 +197,9 @@ function monkeypatch() {
     for (var j = 0; j < node.typeParameters.params.length; j++) {
       var name = node.typeParameters.params[j];
       scope.__define(name, new Definition("TypeParameter", name, name));
+      if (name.typeAnnotation) {
+        checkIdentifierOrVisit.call(this, name);
+      }
     }
     scope.__define = function() {
       return parentScope.__define.apply(parentScope, arguments);
@@ -222,7 +213,7 @@ function monkeypatch() {
     visitDecorators.call(this, node);
     var typeParamScope;
     if (node.typeParameters) {
-      typeParamScope = nestTypeParamScope(this.scopeManager, node);
+      typeParamScope = nestTypeParamScope.call(this, this.scopeManager, node);
     }
     // visit flow type: ClassImplements
     if (node.implements) {
@@ -264,8 +255,7 @@ function monkeypatch() {
   referencer.prototype.visitFunction = function(node) {
     var typeParamScope;
     if (node.typeParameters) {
-      typeParamScope = nestTypeParamScope(this.scopeManager, node);
-      visitTypeParameters.call(this, node.typeParameters);
+      typeParamScope = nestTypeParamScope.call(this, this.scopeManager, node);
     }
     if (node.returnType) {
       checkIdentifierOrVisit.call(this, node.returnType);
@@ -328,11 +318,27 @@ function monkeypatch() {
     );
   }
 
+  referencer.prototype.InterfaceDeclaration = function(node) {
+    createScopeVariable.call(this, node, node.id);
+    var typeParamScope;
+    if (node.typeParameters) {
+      typeParamScope = nestTypeParamScope.call(this, this.scopeManager, node);
+    }
+    // TODO: Handle mixins
+    for (var i = 0; i < node.extends.length; i++) {
+      visitTypeAnnotation.call(this, node.extends[i]);
+    }
+    visitTypeAnnotation.call(this, node.body);
+    if (typeParamScope) {
+      this.close(node);
+    }
+  };
+
   referencer.prototype.TypeAlias = function(node) {
     createScopeVariable.call(this, node, node.id);
     var typeParamScope;
     if (node.typeParameters) {
-      typeParamScope = nestTypeParamScope(this.scopeManager, node);
+      typeParamScope = nestTypeParamScope.call(this, this.scopeManager, node);
     }
     if (node.right) {
       visitTypeAnnotation.call(this, node.right);
@@ -352,7 +358,7 @@ function monkeypatch() {
 
     var typeParamScope;
     if (node.typeParameters) {
-      typeParamScope = nestTypeParamScope(this.scopeManager, node);
+      typeParamScope = nestTypeParamScope.call(this, this.scopeManager, node);
     }
     if (typeParamScope) {
       this.close(node);
diff --git a/test/non-regression.js b/test/non-regression.js
index ba83722a..107802ce 100644
--- a/test/non-regression.js
+++ b/test/non-regression.js
@@ -222,16 +222,73 @@ describe("verify", () => {
       );
     });
 
-    it("type parameter bounds", () => {
+    it("interface declaration", () => {
+      verifyAndAssertMessages(
+        unpad(`
+          interface Foo {};
+          interface Bar {
+            foo: Foo,
+          };
+        `),
+        { "no-unused-vars": 1, "no-undef": 1 },
+        [ "2:11 'Bar' is defined but never used. no-unused-vars" ]
+      );
+    });
+
+    it("type parameter bounds (classes)", () => {
+      verifyAndAssertMessages(
+        unpad(`
+          import type {Foo, Foo2} from 'foo';
+          import Base from 'base';
+          class Log<T1: Foo, T2: Foo2, T3, T4> extends Base<T3> {
+            messages: {[T1]: T2};
+          }
+          new Log();
+        `),
+        { "no-unused-vars": 1, "no-undef": 1 },
+        [ "3:34 'T4' is defined but never used. no-unused-vars" ]
+      );
+    });
+
+    it("type parameter bounds (interfaces)", () => {
+      verifyAndAssertMessages(
+        unpad(`
+          import type {Foo, Foo2, Bar} from '';
+          interface Log<T1: Foo, T2: Foo2, T3, T4> extends Bar<T3> {
+            messages: {[T1]: T2};
+          }
+        `),
+        { "no-unused-vars": 1, "no-undef": 1 },
+        [ "2:11 'Log' is defined but never used. no-unused-vars",
+          "2:38 'T4' is defined but never used. no-unused-vars" ]
+      );
+    });
+
+    it("type parameter bounds (type aliases)", () => {
+      verifyAndAssertMessages(
+        unpad(`
+          import type {Foo, Foo2, Foo3} from 'foo';
+          type Log<T1: Foo, T2: Foo2, T3> = {
+            messages: {[T1]: T2};
+            delay: Foo3;
+          };
+        `),
+        { "no-unused-vars": 1, "no-undef": 1 },
+        [ "2:6 'Log' is defined but never used. no-unused-vars",
+          "2:29 'T3' is defined but never used. no-unused-vars" ]
+      );
+    });
+
+    it("type parameter bounds (functions)", () => {
       verifyAndAssertMessages(
         unpad(`
           import type Foo from 'foo';
           import type Foo2 from 'foo';
-          function log<T1: Foo, T2: Foo2>(a: T1, b: T2) { return a + b; }
+          function log<T1: Foo, T2: Foo2, T3, T4>(a: T1, b: T2): T3 { return a + b; }
           log(1, 2);
         `),
         { "no-unused-vars": 1, "no-undef": 1 },
-        []
+        [ "3:37 'T4' is defined but never used. no-unused-vars" ]
       );
     });