Mark code as normalized after variables are coalesced.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=163026332

src/com/google/javascript/jscomp/CoalesceVariableNames.java

@@ -20,6 +20,7 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.common.base.Joiner;
+import com.google.javascript.jscomp.AbstractCompiler.LifeCycleStage;
 import com.google.javascript.jscomp.ControlFlowGraph.AbstractCfgNodeTraversalCallback;
 import com.google.javascript.jscomp.ControlFlowGraph.Branch;
 import com.google.javascript.jscomp.DataFlowAnalysis.FlowState;
@@ -82,10 +83,10 @@ public int compare(Var v1, Var v2) {
    * to foo, rename both variable to foo_bar.
    */
   CoalesceVariableNames(AbstractCompiler compiler, boolean usePseudoNames) {
-    // The code is normalized at this point in the compilation process, however as a result of this
-    // pass, the code becomes unnormalized (since we are reusing variable names) and so we want to
-    // unconditionally mark the code as unnormalized. We mark unnormalized right before this pass.
-    checkState(!compiler.getLifeCycleStage().isNormalized());
+    // The code is normalized at this point in the compilation process. This allows us to use the
+    // fact that all variables have been given unique names. We can hoist coalesced variables to
+    // VARS because we know that shadowing can't occur.
+    checkState(compiler.getLifeCycleStage().isNormalized());
 
     this.compiler = compiler;
     colorings = new LinkedList<>();
@@ -98,6 +99,7 @@ public void process(Node externs, Node root) {
     checkNotNull(externs);
     checkNotNull(root);
     NodeTraversal.traverseEs6(compiler, root, this);
+    compiler.setLifeCycleStage(LifeCycleStage.RAW);
   }
 
   private static boolean shouldOptimizeScope(NodeTraversal t) {

src/com/google/javascript/jscomp/DefaultPassConfig.java

@@ -828,11 +828,9 @@ protected List<PassFactory> getOptimizations() {
       passes.add(aliasStrings);
     }
 
-    // Passes after this point can no longer depend on normalized AST
-    // assumptions.
-    passes.add(markUnnormalized);
-
     if (options.coalesceVariableNames) {
+      // Passes after this point can no longer depend on normalized AST
+      // assumptions because the code is marked as un-normalized
       passes.add(coalesceVariableNames);
 
       // coalesceVariables creates identity assignments and more redundant code
@@ -841,6 +839,10 @@ protected List<PassFactory> getOptimizations() {
       if (options.foldConstants) {
         passes.add(peepholeOptimizationsOnce);
       }
+    } else {
+      // Passes after this point can no longer depend on normalized AST
+      // assumptions.
+      passes.add(markUnnormalized);
     }
 
     if (options.collapseVariableDeclarations) {
@@ -2830,25 +2832,24 @@ protected CompilerPass create(AbstractCompiler compiler) {
         }
       };
 
-  /**
-   * Mark the point at which the normalized AST assumptions no longer hold.
-   */
+  /** Mark the point at which the normalized AST assumptions no longer hold. */
   private final PassFactory markUnnormalized =
       new PassFactory("markUnnormalized", true) {
-    @Override
-    protected CompilerPass create(final AbstractCompiler compiler) {
-      return new CompilerPass() {
-        @Override public void process(Node externs, Node root) {
-          compiler.setLifeCycleStage(LifeCycleStage.RAW);
+        @Override
+        protected CompilerPass create(final AbstractCompiler compiler) {
+          return new CompilerPass() {
+            @Override
+            public void process(Node externs, Node root) {
+              compiler.setLifeCycleStage(LifeCycleStage.RAW);
+            }
+          };
         }
-      };
-    }
 
-    @Override
-    protected FeatureSet featureSet() {
-      return FeatureSet.latest();
-    }
-  };
+        @Override
+        protected FeatureSet featureSet() {
+          return FeatureSet.latest();
+        }
+      };
 
   private final PassFactory hoistVars =
       new PassFactory("hoistVars", true) {