Switch to Es6SyntacticScopeCreator in InlineVariables.

Part of #950

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=155096028

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

@@ -84,7 +84,7 @@ public void process(Node externs, Node root) {
         new ReferenceCollectingCallback(
             compiler,
             new InliningBehavior(),
-            SyntacticScopeCreator.makeUntyped(compiler),
+            new Es6SyntacticScopeCreator(compiler),
             getFilterForMode());
     callback.process(externs, root);
   }

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

@@ -240,15 +240,22 @@ private void outOfBandTraversal(Var v) {
   public void enterScope(NodeTraversal t) {
     Node n = t.getScopeRoot();
     BasicBlock parent = blockStack.isEmpty() ? null : peek(blockStack);
-    blockStack.add(new BasicBlock(parent, n));
+    // Don't add all ES6 scope roots to blockStack, only those that are also scopes according to
+    // the ES5 scoping rules. Other nodes that ought to be considered the root of a BasicBlock
+    // are added in shouldTraverse() and removed in visit().
+    if (t.getScope().isHoistScope()) {
+      blockStack.add(new BasicBlock(parent, n));
+    }
   }
 
   /**
    * Updates block stack and invokes any additional behavior.
    */
   @Override
   public void exitScope(NodeTraversal t) {
-    pop(blockStack);
+    if (t.getScope().isHoistScope()) {
+      pop(blockStack);
+    }
     if (t.inGlobalScope()) {
       // Update global scope reference lists when we are done with it.
       compiler.updateGlobalVarReferences(referenceMap, t.getScopeRoot());
@@ -845,6 +852,7 @@ static final class BasicBlock {
             pType == Token.DO
                 || pType == Token.WHILE
                 || pType == Token.FOR
+                || pType == Token.FOR_OF
                 || pType == Token.FOR_IN;
       } else {
         this.isLoop = false;

test/com/google/javascript/jscomp/InlineVariablesTest.java

@@ -16,6 +16,7 @@
 
 package com.google.javascript.jscomp;
 
+import static com.google.javascript.jscomp.CompilerOptions.LanguageMode.ECMASCRIPT_NEXT;
 
 /**
  * Verifies that valid candidates for inlining are inlined, but
@@ -31,6 +32,7 @@ public final class InlineVariablesTest extends CompilerTestCase {
 
   public InlineVariablesTest() {
     enableNormalize();
+    setAcceptedLanguage(ECMASCRIPT_NEXT);
   }
 
   @Override
@@ -825,14 +827,94 @@ public void testInlineSwitchVar() {
         "switch (y) {}");
   }
 
-  public void testInlineCatchAlias1() {
+  public void testInlineSwitchLet() {
     test(
+        "let x = y; switch (x) {}",
+        "switch (y) {}");
+  }
+
+  // Successfully inlines 'values' and 'e'
+  public void testInlineIntoForLoop1() {
+    test(
+        LINE_JOINER.join(
+            "function calculate_hashCode() {",
+            "  var values = [1, 2, 3, 4, 5];",
+            "  var hashCode = 1;",
+            "  for (var $array = values, i = 0; i < $array.length; i++) {",
+            "    var e = $array[i];",
+            "    hashCode = 31 * hashCode + calculate_hashCode(e);",
+            "  }",
+            "  return hashCode;",
+            "}"),
+        LINE_JOINER.join(
+            "function calculate_hashCode() {",
+            "  var hashCode = 1;",
+            "  var $array = [1, 2, 3, 4, 5];",
+            "  var i = 0;",
+            "  for (; i < $array.length; i++) {",
+            "    hashCode = 31 * hashCode + calculate_hashCode($array[i]);",
+            "  }",
+            "  return hashCode;",
+            "}"));
+  }
+
+  // Inlines 'e' but fails to inline 'values'
+  // TODO(tbreisacher): Investigate and see if we can improve this.
+  public void testInlineIntoForLoop2() {
+    test(
+        LINE_JOINER.join(
+            "function calculate_hashCode() {",
+            "  let values = [1, 2, 3, 4, 5];",
+            "  let hashCode = 1;",
+            "  for (let $array = values, i = 0; i < $array.length; i++) {",
+            "    let e = $array[i];",
+            "    hashCode = 31 * hashCode + calculate_hashCode(e);",
+            "  }",
+            "  return hashCode;",
+            "}"),
+        LINE_JOINER.join(
+            "function calculate_hashCode() {",
+            "  let values = [1, 2, 3, 4, 5];",
+            "  let hashCode = 1;",
+            "  for (let $array = values, i = 0; i < $array.length; i++) {",
+            "    hashCode = 31 * hashCode + calculate_hashCode($array[i]);",
+            "  }",
+            "  return hashCode;",
+            "}"));
+  }
+
+  // This used to be inlined, but regressed when we switched to the ES6 scope creator.
+  public void testNoInlineCatchAliasVar1() {
+    testSame(
         LINE_JOINER.join(
             "try {",
             "} catch (e) {",
             "  var y = e;",
             "  g();" ,
             "  y;y;" ,
+            "}"));
+  }
+
+  // This used to be inlined, but regressed when we switched to the ES6 scope creator.
+  public void testNoInlineCatchAliasVar2() {
+    testSame(
+        LINE_JOINER.join(
+            "try {",
+            "} catch (e) {",
+            "  var y; y = e;",
+            "  g();",
+            "  y;y;",
+            "}"));
+  }
+
+  public void testInlineCatchAliasLet1() {
+    test(
+        LINE_JOINER.join(
+            "try {",
+            "} catch (e) {",
+            "  let y = e;",
+            "  g();" ,
+            "  y;y;" ,
             "}"),
         LINE_JOINER.join(
             "try {",
@@ -842,12 +924,12 @@ public void testInlineCatchAlias1() {
             "}"));
   }
 
-  public void testInlineCatchAlias2() {
+  public void testInlineCatchAliasLet2() {
     test(
         LINE_JOINER.join(
             "try {",
             "} catch (e) {",
-            "  var y; y = e;",
+            "  let y; y = e;",
             "  g();",
             "  y;y;",
             "}"),

test/com/google/javascript/jscomp/ReferenceCollectingCallbackTest.java

@@ -270,29 +270,12 @@ public void afterExitScope(NodeTraversal t, ReferenceMap rm) {
   }
 
   public void testBasicBlocks() {
-    testBehavior(
-        LINE_JOINER.join(
-            "var x = 0;",
-            "switch (x) {",
-            "  case 0:",
-            "    x;",
-            "}"),
-        new Behavior() {
-          @Override
-          public void afterExitScope(NodeTraversal t, ReferenceMap rm) {
-            if (t.getScope().isGlobal()) {
-              ReferenceCollection x = rm.getReferences(t.getScope().getVar("x"));
-              assertThat(x.references).hasSize(3);
-              assertNode(x.references.get(0).getBasicBlock().getRoot()).hasType(Token.ROOT);
-              assertNode(x.references.get(1).getBasicBlock().getRoot()).hasType(Token.SWITCH);
-              assertNode(x.references.get(2).getBasicBlock().getRoot()).hasType(Token.CASE);
-            }
-          }
-        });
+    testBasicBlocks(true);
+    testBasicBlocks(false);
   }
 
-  public void testBasicBlocks_oldScopeCreator() {
-    es6ScopeCreator = false;
+  private void testBasicBlocks(boolean scopeCreator) {
+    es6ScopeCreator = scopeCreator;
     testBehavior(
         LINE_JOINER.join(
             "var x = 0;",