From 04a053aa7f297d04631c9f226915ecd3ba593006 Mon Sep 17 00:00:00 2001
From: blickly <blickly@google.com>
Date: Mon, 9 Jan 2017 13:48:26 -0800
Subject: [PATCH] In externs, allow stub definitions for goog.provided names to
 not have an RHS.

This is needed to properly check .i.js files.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=144003191
---
 .../jscomp/ProcessClosurePrimitives.java          | 15 ++++++++++-----
 .../google/javascript/jscomp/IntegrationTest.java | 12 ++++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/com/google/javascript/jscomp/ProcessClosurePrimitives.java b/src/com/google/javascript/jscomp/ProcessClosurePrimitives.java
index ce112221fa5..574e5da8005 100644
--- a/src/com/google/javascript/jscomp/ProcessClosurePrimitives.java
+++ b/src/com/google/javascript/jscomp/ProcessClosurePrimitives.java
@@ -317,7 +317,7 @@ public void visit(NodeTraversal t, Node n, Node parent) {
         break;
 
       case EXPR_RESULT:
-        handleTypedefDefinition(t, n);
+        handleStubDefinition(t, n);
         break;
 
       case CLASS:
@@ -486,13 +486,18 @@ private void processDefineCall(NodeTraversal t, Node n, Node parent) {
   }
 
   /**
-   * Handles a typedef definition for a goog.provided name.
+   * Handles a stub definition for a goog.provided name
+   * (e.g. a @typedef or a definition from externs)
+   *
    * @param n EXPR_RESULT node.
    */
-  private void handleTypedefDefinition(
-      NodeTraversal t, Node n) {
+  private void handleStubDefinition(NodeTraversal t, Node n) {
+    if (!t.inGlobalHoistScope()) {
+      return;
+    }
     JSDocInfo info = n.getFirstChild().getJSDocInfo();
-    if (t.inGlobalHoistScope() && info != null && info.hasTypedefType()) {
+    boolean hasStubDefinition = info != null && (n.isFromExterns() || info.hasTypedefType());
+    if (hasStubDefinition) {
       String name = n.getFirstChild().getQualifiedName();
       if (name != null) {
         ProvidedName pn = providedNames.get(name);
diff --git a/test/com/google/javascript/jscomp/IntegrationTest.java b/test/com/google/javascript/jscomp/IntegrationTest.java
index a5be9374b81..230e9f7b2a1 100644
--- a/test/com/google/javascript/jscomp/IntegrationTest.java
+++ b/test/com/google/javascript/jscomp/IntegrationTest.java
@@ -3852,6 +3852,18 @@ public void testEs6OutDoesntCrash() {
     test(options, "function f(x) { if (x) var x=5; }", "function f(x) { if (x) x=5; }");
   }
 
+  public void testExternsProvideIsAllowed() {
+    CompilerOptions options = createCompilerOptions();
+    options.setIncrementalChecks(CompilerOptions.IncrementalCheckMode.CHECK_IJS);
+    options.setClosurePass(true);
+    options.setCheckTypes(true);
+
+    externs = ImmutableList.of(SourceFile.fromCode("<externs>",
+        "goog.provide('foo.bar'); /** @type {!Array<number>} */ foo.bar;"));
+
+    test(options, "", "");
+  }
+
   // GitHub issue #250: https://github.com/google/closure-compiler/issues/250
   public void testInlineStringConcat() {
     CompilerOptions options = createCompilerOptions();