[parser] Skipping inner funcs: produce the same scopes / variables for this expressions.

BUG=v8:5516
R=vogelheim@chromium.org

Review-Url: https://codereview.chromium.org/2683563002
Cr-Commit-Position: refs/heads/master@{#42983}

src/parsing/preparser.h

@@ -203,9 +203,10 @@ class PreParserExpression {
                                IsUseAsmField::encode(true));
   }
 
-  static PreParserExpression This() {
+  static PreParserExpression This(ZoneList<VariableProxy*>* variables) {
     return PreParserExpression(TypeField::encode(kExpression) |
-                               ExpressionTypeField::encode(kThisExpression));
+                                   ExpressionTypeField::encode(kThisExpression),
+                               variables);
   }
 
   static PreParserExpression ThisProperty() {
@@ -1494,7 +1495,19 @@ class PreParser : public ParserBase<PreParser> {
   }
 
   V8_INLINE PreParserExpression ThisExpression(int pos = kNoSourcePosition) {
-    return PreParserExpression::This();
+    ZoneList<VariableProxy*>* variables = nullptr;
+    if (track_unresolved_variables_) {
+      AstNodeFactory factory(ast_value_factory());
+      // Setting the Zone is necessary because zone_ might be the temp Zone, and
+      // AstValueFactory doesn't know about it.
+      factory.set_zone(zone());
+      VariableProxy* proxy = scope()->NewUnresolved(
+          &factory, ast_value_factory()->this_string(), pos, THIS_VARIABLE);
+
+      variables = new (zone()) ZoneList<VariableProxy*>(1, zone());
+      variables->Add(proxy, zone());
+    }
+    return PreParserExpression::This(variables);
   }
 
   V8_INLINE PreParserExpression NewSuperPropertyReference(int pos) {

test/cctest/test-parsing.cc

@@ -9258,12 +9258,19 @@ TEST(PreParserScopeAnalysis) {
       {"", "var var1; if (true) { const var1 = 0; }"},
       {"", "const var1 = 0; if (true) { const var1 = 0; }"},
 
-      // Variable called "arguments"
+      // Arguments and this.
       {"", "arguments;"},
       {"", "arguments = 5;"},
+      {"", "if (true) { arguments; }"},
+      {"", "if (true) { arguments = 5; }"},
       {"", "function f() { arguments; }"},
       {"", "function f() { arguments = 5; }"},
 
+      {"", "this;"},
+      {"", "if (true) { this; }"},
+      {"", "function f() { this; }"},
+
+      // Variable called "arguments"
       {"", "var arguments;"},
       {"", "var arguments; arguments = 5;"},
       {"", "if (true) { var arguments; }"},
@@ -9435,9 +9442,6 @@ TEST(PreParserScopeAnalysis) {
       {"",
        "var var1 = 0; for (var1; var1 > 2; ) { function foo() { var1 = 6; } }"},
 
-      // FIXME(marja): Add test cases for special variables (this, arguments
-      // etc) referred to in the for loop conditions.
-
       // Sloppy block functions.
       {"", "if (true) { function f1() {} }"},
       {"", "if (true) { function f1() {} function f1() {} }"},