From 6797f5b2932c4dcdc12a3d4f9580d7fb9ae4bbf8 Mon Sep 17 00:00:00 2001
From: blickly <blickly@google.com>
Date: Fri, 2 Mar 2018 14:54:33 -0800
Subject: [PATCH] Fix a crash in ScopedAliases when run in type-only summary
 generation mode

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=187673532
---
 .../javascript/jscomp/ScopedAliases.java      | 33 +++++++++++++----
 .../javascript/jscomp/ScopedAliasesTest.java  | 37 ++++++++++++++++++-
 2 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/src/com/google/javascript/jscomp/ScopedAliases.java b/src/com/google/javascript/jscomp/ScopedAliases.java
index 13a2f3974aa..3833f8c90f9 100644
--- a/src/com/google/javascript/jscomp/ScopedAliases.java
+++ b/src/com/google/javascript/jscomp/ScopedAliases.java
@@ -221,21 +221,40 @@ public boolean referencesOtherAlias() {
     public abstract void applyAlias(AbstractCompiler compiler);
   }
 
+  private static boolean isValidAliasRhs(Node rhs) {
+    switch (rhs.getToken()) {
+      case GETPROP:
+        return isValidAliasRhs(rhs.getFirstChild());
+      case NAME:
+        return true;
+      case CALL:
+        return NodeUtil.isCallTo(rhs, "goog.module.get");
+      default:
+        return false;
+    }
+  }
+
   private static boolean isAliasDefinition(Node nameNode) {
     if (!nameNode.hasChildren()) {
       return false;
     }
     Node rhs = nameNode.getLastChild();
-    return rhs.isQualifiedName() || NodeUtil.isCallTo(rhs, "goog.module.get");
+    return isValidAliasRhs(rhs);
   }
 
-  private static String getAliasedNamespace(Node aliasDefinition) {
-    if (aliasDefinition.isQualifiedName()) {
-      return aliasDefinition.getQualifiedName();
+  private static String getAliasedNamespace(Node rhs) {
+    switch (rhs.getToken()) {
+      case GETPROP:
+        return getAliasedNamespace(rhs.getFirstChild()) + '.' + rhs.getLastChild().getString();
+      case NAME:
+        return rhs.getString();
+      case CALL:
+        checkState(NodeUtil.isCallTo(rhs, "goog.module.get"), rhs);
+        checkState(rhs.hasTwoChildren(), rhs);
+        return rhs.getLastChild().getString();
+      default:
+        throw new RuntimeException("Invalid alias RHS:" + rhs);
     }
-    checkState(NodeUtil.isCallTo(aliasDefinition, "goog.module.get"), aliasDefinition);
-    checkState(aliasDefinition.hasTwoChildren(), aliasDefinition);
-    return aliasDefinition.getLastChild().getString();
   }
 
   private static class AliasedNode extends AliasUsage {
diff --git a/test/com/google/javascript/jscomp/ScopedAliasesTest.java b/test/com/google/javascript/jscomp/ScopedAliasesTest.java
index e071e6acdcd..66725392860 100644
--- a/test/com/google/javascript/jscomp/ScopedAliasesTest.java
+++ b/test/com/google/javascript/jscomp/ScopedAliasesTest.java
@@ -1010,7 +1010,7 @@ public void testIssue2211c() {
             "});"));
   }
 
-  public void testGoogModuleGet() {
+  public void testGoogModuleGet1() {
     test(
         lines(
             "goog.provide('provided');",
@@ -1027,6 +1027,41 @@ public void testGoogModuleGet() {
             ""));
   }
 
+  public void testGoogModuleGet2() {
+    test(
+        lines(
+            "goog.provide('foo.baz');",
+            "",
+            "goog.scope(function() {",
+            "",
+            "const a = goog.module.get('other.thing');",
+            "const b = a.b;",
+            "foo.baz = b",
+            "",
+            "}); // goog.scope"),
+        lines(
+            "goog.provide('foo.baz');",
+            "foo.baz = goog.module.get('other.thing').b;",
+            ""));
+  }
+
+  public void testGoogModuleGet3() {
+    test(
+        lines(
+            "goog.provide('foo.baz');",
+            "",
+            "goog.scope(function() {",
+            "",
+            "const a = goog.module.get('other.thing').b;",
+            "foo.baz = a",
+            "",
+            "}); // goog.scope"),
+        lines(
+            "goog.provide('foo.baz');",
+            "foo.baz = goog.module.get('other.thing').b;",
+            ""));
+  }
+
   public void testObjectPattern() {
     testScopedNoChanges("", "{foo: ({bar}) => baz};");
   }