diff --git a/src/com/google/javascript/jscomp/ClosureCheckModule.java b/src/com/google/javascript/jscomp/ClosureCheckModule.java
index f0539abfe11..f0e396538e4 100644
--- a/src/com/google/javascript/jscomp/ClosureCheckModule.java
+++ b/src/com/google/javascript/jscomp/ClosureCheckModule.java
@@ -128,9 +128,20 @@ public final class ClosureCheckModule extends AbstractModuleCallback
 
   private final AbstractCompiler compiler;
 
-  private String currentModuleName = null;
-  private Map<String, String> shortRequiredNamespaces = new HashMap<>();
-  private Node defaultExportNode = null;
+  private static class ModuleInfo {
+    // Name of the module in question (i.e. the argument to goog.module)
+    private final String name;
+    // Mapping from fully qualified goog.required names to the import LHS node
+    private final Map<String, Node> importsByLongRequiredName = new HashMap<>();
+    // The node of the default (non-named) export of this module, if it exists.
+    private Node defaultExportNode = null;
+
+    ModuleInfo(String moduleName) {
+      this.name = moduleName;
+    }
+  }
+
+  private ModuleInfo currentModule = null;
 
   public ClosureCheckModule(AbstractCompiler compiler) {
     this.compiler = compiler;
@@ -153,22 +164,25 @@ public void enterModule(NodeTraversal t, Node scopeRoot) {
       Node call = firstStatement.getFirstChild();
       Node callee = call.getFirstChild();
       if (callee.matchesQualifiedName("goog.module")) {
-        Preconditions.checkState(currentModuleName == null);
-        currentModuleName = extractFirstArgumentName(call);
+        Preconditions.checkState(currentModule == null);
+        String moduleName = extractFirstArgumentName(call);
+        if (moduleName == null) {
+          t.report(scopeRoot, ClosureRewriteModule.INVALID_MODULE_NAMESPACE);
+        } else {
+          currentModule = new ModuleInfo(moduleName);
+        }
       }
     }
   }
 
   @Override
   public void exitModule(NodeTraversal t, Node scopeRoot) {
-    currentModuleName = null;
-    shortRequiredNamespaces.clear();
-    defaultExportNode = null;
+    currentModule = null;
   }
 
   @Override
   public void visit(NodeTraversal t, Node n, Node parent) {
-    if (currentModuleName == null) {
+    if (currentModule == null) {
       return;
     }
     JSDocInfo jsDoc = n.getJSDocInfo();
@@ -179,7 +193,7 @@ public void visit(NodeTraversal t, Node n, Node parent) {
       case CALL:
         Node callee = n.getFirstChild();
         if (callee.matchesQualifiedName("goog.module")
-            && !currentModuleName.equals(extractFirstArgumentName(n))) {
+            && !currentModule.name.equals(extractFirstArgumentName(n))) {
           t.report(n, MULTIPLE_MODULES_IN_FILE);
         } else if (callee.matchesQualifiedName("goog.provide")) {
           t.report(n, MODULE_AND_PROVIDES);
@@ -224,15 +238,15 @@ public void visit(NodeTraversal t, Node n, Node parent) {
         }
         break;
       case GETPROP:
-        if (currentModuleName != null && n.matchesQualifiedName(currentModuleName)) {
+        if (n.matchesQualifiedName(currentModule.name)) {
           t.report(n, REFERENCE_TO_MODULE_GLOBAL_NAME);
-        } else if (shortRequiredNamespaces.containsKey(n.getQualifiedName())) {
-          String shortName = shortRequiredNamespaces.get(n.getQualifiedName());
-          if (shortName == null) {
+        } else if (currentModule.importsByLongRequiredName.containsKey(n.getQualifiedName())) {
+          Node importLhs = currentModule.importsByLongRequiredName.get(n.getQualifiedName());
+          if (importLhs == null || !importLhs.isName()) {
             t.report(n, REFERENCE_TO_FULLY_QUALIFIED_IMPORT_NAME, n.getQualifiedName());
           } else {
             t.report(n, REFERENCE_TO_SHORT_IMPORT_BY_LONG_NAME_INCLUDING_SHORT_NAME,
-                n.getQualifiedName(), shortName);
+                n.getQualifiedName(), importLhs.getQualifiedName());
           }
         }
         break;
@@ -240,6 +254,7 @@ public void visit(NodeTraversal t, Node n, Node parent) {
         break;
     }
   }
+
   private void checkJSDoc(NodeTraversal t, JSDocInfo jsDoc) {
     for (Node typeNode : jsDoc.getTypeNodes()) {
       checkTypeExpression(t, typeNode);
@@ -257,16 +272,16 @@ public void visit(Node node) {
             }
             String type = node.getString();
             while (true) {
-              if (shortRequiredNamespaces.containsKey(type)) {
-                String shortName = shortRequiredNamespaces.get(type);
-                if (shortName == null) {
+              if (currentModule.importsByLongRequiredName.containsKey(type)) {
+                Node importLhs = currentModule.importsByLongRequiredName.get(type);
+                if (importLhs == null || !importLhs.isName()) {
                   t.report(node, JSDOC_REFERENCE_TO_FULLY_QUALIFIED_IMPORT_NAME, type);
-                } else if (!shortName.equals(type)) {
+                } else if (!importLhs.getString().equals(type)) {
                   t.report(
                       node,
                       JSDOC_REFERENCE_TO_SHORT_IMPORT_BY_LONG_NAME_INCLUDING_SHORT_NAME,
                       type,
-                      shortName);
+                      importLhs.getString());
                 }
               }
               if (type.contains(".")) {
@@ -293,16 +308,17 @@ private void checkModuleExport(NodeTraversal t, Node n, Node parent) {
     Preconditions.checkArgument(n.isAssign());
     Node lhs = n.getFirstChild();
     Preconditions.checkState(isExportLhs(lhs));
-    if (defaultExportNode == null && (!t.inModuleScope() || !parent.isExprResult())) {
+    if (currentModule.defaultExportNode == null && (!t.inModuleScope() || !parent.isExprResult())) {
       // Invalid export location.
       t.report(n, EXPORT_NOT_A_MODULE_LEVEL_STATEMENT);
     }
     if (lhs.isName()) {
-      if  (defaultExportNode != null) {
+      if  (currentModule.defaultExportNode != null) {
         // Multiple exports
-        t.report(n, EXPORT_REPEATED_ERROR, String.valueOf(defaultExportNode.getLineno()));
+        int previousLine = currentModule.defaultExportNode.getLineno();
+        t.report(n, EXPORT_REPEATED_ERROR, String.valueOf(previousLine));
       }
-      defaultExportNode = lhs;
+      currentModule.defaultExportNode = lhs;
     }
     if ((lhs.isName() || !NodeUtil.isPrototypeProperty(lhs))
         && !NodeUtil.isLegacyGoogModuleFile(NodeUtil.getEnclosingScript(n))) {
@@ -338,7 +354,7 @@ private void checkRequireCall(NodeTraversal t, Node callNode, Node parent) {
   }
 
   private void checkShortGoogRequireCall(NodeTraversal t, Node callNode, Node declaration) {
-    String shortName = null;
+    Node lhs = null;
     if (NodeUtil.isNameDeclaration(declaration)) {
       if (declaration.isLet()
           && !callNode.getFirstChild().matchesQualifiedName("goog.forwardDeclare")) {
@@ -347,13 +363,12 @@ private void checkShortGoogRequireCall(NodeTraversal t, Node callNode, Node decl
       if (!declaration.hasOneChild()) {
         t.report(declaration, ONE_REQUIRE_PER_DECLARATION);
       }
-      Node lhs = declaration.getFirstChild();
+      lhs = declaration.getFirstChild();
       if (lhs.isDestructuringLhs() && !isValidDestructuringImport(lhs)) {
         t.report(declaration, INVALID_DESTRUCTURING_REQUIRE);
       }
-      shortName = lhs.isName() ? lhs.getString() : null;
     }
-    shortRequiredNamespaces.put(extractFirstArgumentName(callNode), shortName);
+    currentModule.importsByLongRequiredName.put(extractFirstArgumentName(callNode), lhs);
   }
 
   private static boolean isValidDestructuringImport(Node destructuringLhs) {