Implement handling of arrow functions in the parser

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index e26ad03dd3878d029c647151f5db6f9fe8a5566b..efbbc94414a6cf886f249a5ccb8da5681009196e 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -194,6 +194,7 @@ class ScriptResource : public v8::String::ExternalAsciiStringResource {
 
 
 TEST(UsingCachedData) {
+  i::FLAG_harmony_arrow_functions = true;
   v8::Isolate* isolate = CcTest::isolate();
   v8::HandleScope handles(isolate);
   v8::Local<v8::Context> context = v8::Context::New(isolate);
@@ -242,6 +243,7 @@ TEST(PreparseFunctionDataIsUsed) {
   // Make preparsing work for short scripts.
   i::FLAG_min_preparse_length = 0;
 
+  i::FLAG_harmony_arrow_functions = true;
   v8::Isolate* isolate = CcTest::isolate();
   v8::HandleScope handles(isolate);
   v8::Local<v8::Context> context = v8::Context::New(isolate);
@@ -250,31 +252,38 @@ TEST(PreparseFunctionDataIsUsed) {
   CcTest::i_isolate()->stack_guard()->SetStackLimit(
       reinterpret_cast<uintptr_t>(&marker) - 128 * 1024);
 
-  const char* good_code =
-      "function this_is_lazy() { var a; } function foo() { return 25; } foo();";
+  const char* good_code[] = {
+    "function this_is_lazy() { var a; } function foo() { return 25; } foo();",
+    NULL

[marja, 2014/06/17 11:47:38]

What, why? What are the changes in this test?

+  };
 
   // Insert a syntax error inside the lazy function.
-  const char* bad_code =
-      "function this_is_lazy() { if (   } function foo() { return 25; } foo();";
+  const char* bad_code[] = {
+    "function this_is_lazy() { if (   } function foo() { return 25; } foo();",
+    NULL
+  };
 
-  v8::ScriptCompiler::Source good_source(v8_str(good_code));
-  v8::ScriptCompiler::Compile(isolate, &good_source,
-                              v8::ScriptCompiler::kProduceDataToCache);
+  for (int i = 0; good_code[i]; i++) {

[marja, 2014/06/17 11:47:38]

Looping over an array that has only 1 non-trivial element?

+    v8::ScriptCompiler::Source good_source(v8_str(good_code[i]));
+    v8::ScriptCompiler::Compile(isolate, &good_source,
+                                v8::ScriptCompiler::kProduceDataToCache);
 
-  const v8::ScriptCompiler::CachedData* cached_data =
-      good_source.GetCachedData();
-  CHECK(cached_data->data != NULL);
-  CHECK_GT(cached_data->length, 0);
+    const v8::ScriptCompiler::CachedData* cached_data =
+        good_source.GetCachedData();
+    CHECK(cached_data->data != NULL);
+    CHECK_GT(cached_data->length, 0);
 
-  // Now compile the erroneous code with the good preparse data. If the preparse
-  // data is used, the lazy function is skipped and it should compile fine.
-  v8::ScriptCompiler::Source bad_source(
-      v8_str(bad_code), new v8::ScriptCompiler::CachedData(
-                            cached_data->data, cached_data->length));
-  v8::Local<v8::Value> result =
-      v8::ScriptCompiler::Compile(isolate, &bad_source)->Run();
-  CHECK(result->IsInt32());
-  CHECK_EQ(25, result->Int32Value());
+    // Now compile the erroneous code with the good preparse data. If the
+    // preparse data is used, the lazy function is skipped and it should
+    // compile fine.
+    v8::ScriptCompiler::Source bad_source(
+        v8_str(bad_code[i]), new v8::ScriptCompiler::CachedData(
+                              cached_data->data, cached_data->length));
+    v8::Local<v8::Value> result =
+        v8::ScriptCompiler::Compile(isolate, &bad_source)->Run();
+    CHECK(result->IsInt32());
+    CHECK_EQ(25, result->Int32Value());
+  }
 }
 
 
@@ -291,6 +300,7 @@ TEST(StandAlonePreParser) {
       "function foo(x, y) { return x + y; }",
       "%ArgleBargle(glop);",
       "var x = new new Function('this.x = 42');",
+      "var f = (x, y) => x + y;",
       NULL
   };
 
@@ -307,6 +317,7 @@ TEST(StandAlonePreParser) {
     i::PreParser preparser(&scanner, &log, stack_limit);
     preparser.set_allow_lazy(true);
     preparser.set_allow_natives_syntax(true);
+    preparser.set_allow_arrow_functions(true);
     i::PreParser::PreParseResult result = preparser.PreParseProgram();
     CHECK_EQ(i::PreParser::kPreParseSuccess, result);
     i::ScriptData data(log.ExtractData());
@@ -967,7 +978,13 @@ TEST(ScopePositions) {
       "    infunction;\n"
       "  }", "\n"
       "  more;", i::FUNCTION_SCOPE, i::SLOPPY },
-    { "  (function fun", "(a,b) { infunction; }", ")();",
+    // TODO(aperez): Change to use i::ARROW_SCOPE when implemented
+    { "  start;\n", "(a,b) => a + b", "; more;",
+      i::FUNCTION_SCOPE, i::SLOPPY },
+    { "  start;\n", "(a,b) => { return a+b; }", "\nmore;",
+      i::FUNCTION_SCOPE, i::SLOPPY },
+    { "  start;\n"
+      "  (function fun", "(a,b) { infunction; }", ")();",
       i::FUNCTION_SCOPE, i::SLOPPY },
     { "  for ", "(let x = 1 ; x < 10; ++ x) { block; }", " more;",
       i::BLOCK_SCOPE, i::STRICT },
@@ -1122,6 +1139,7 @@ TEST(ScopePositions) {
     i::Parser parser(&info);
     parser.set_allow_lazy(true);
     parser.set_allow_harmony_scoping(true);
+    parser.set_allow_arrow_functions(true);
     info.MarkAsGlobal();
     info.SetStrictMode(source_data[i].strict_mode);
     parser.Parse();
@@ -1199,6 +1217,7 @@ void SetParserFlags(i::ParserBase<Traits>* parser,
   parser->set_allow_for_of(flags.Contains(kAllowForOf));
   parser->set_allow_harmony_numeric_literals(
       flags.Contains(kAllowHarmonyNumericLiterals));
+  parser->set_allow_arrow_functions(i::FLAG_harmony_arrow_functions);

[marja, 2014/06/17 11:47:38]

We'd probably like to run each existing ParserSyncTest both with and without
arrow functions, so you should handle it like the flags above (add a flag for it
into "flags" here).

But I realize it's actually not as easy as it should be, because for some tests
we want to pin some flags (so that other flags vary but those are always true).

I can try to add the machinery for that (an "alwaysTrueFlags" array which
overrides the varying flags) and see how it looks.

 }
 
 
@@ -1526,6 +1545,10 @@ TEST(ErrorsEvalAndArguments) {
     "function foo(arguments) { }",
     "function foo(bar, eval) { }",
     "function foo(bar, arguments) { }",
+    "(eval) => { }",
+    "(arguments) => { }",
+    "(foo, eval) => { }",
+    "(foo, arguments) => { }",
     "eval = 1;",
     "arguments = 1;",
     "var foo = eval = 1;",
@@ -2018,6 +2041,7 @@ TEST(DontRegressPreParserDataSizes) {
 
 
 TEST(FunctionDeclaresItselfStrict) {
+  i::FLAG_harmony_arrow_functions = true;
   // Tests that we produce the right kinds of errors when a function declares
   // itself strict (we cannot produce there errors as soon as we see the
   // offending identifiers, because we don't know at that point whether the
@@ -2036,6 +2060,20 @@ TEST(FunctionDeclaresItselfStrict) {
     {"function foo(bar, yield) {", "}"},
     {"function foo(bar, interface) {", "}"},
     {"function foo(bar, bar) {", "}"},
+    {"eval => {", "}"},

[marja, 2014/06/17 11:47:38]

You could have a separate test case for these, and remove the i::FLAG above (so
that the main test case would be both with and without the arrow function flag).

+    {"arguments => {", "}"},
+    {"yield => {", "}"},
+    {"interface => {", "}"},
+    {"(eval) => {", "}"},
+    {"(arguments) => {", "}"},
+    {"(yield) => {", "}"},
+    {"(interface) => {", "}"},
+    {"(eval, bar) => {", "}"},
+    {"(bar, eval) => {", "}"},
+    {"(bar, arguments) => {", "}"},
+    {"(bar, yield) => {", "}"},
+    {"(bar, interface) => {", "}"},
+    {"(bar, bar) => {", "}"},
     { NULL, NULL }
   };
 
@@ -2550,3 +2588,96 @@ TEST(FuncNameInferrerEscaped) {
   i::DeleteArray(two_byte_source);
   i::DeleteArray(two_byte_name);
 }
+
+
+TEST(ErrorsArrowFunctions) {
+  // Tests that parser and preparser generate the same kind of errors
+  // on invalid arrow function syntax.
+  i::FLAG_harmony_arrow_functions = true;
+
+  const char* context_data[][2] = {
+    {"", ";"},
+    {"v = ", ";"},
+    {"bar ? (", ") : baz;"},
+    {"bar ? baz : (", ");"},
+    {"bar[", "];"},
+    {"bar, ", ";"},
+    {"", ", bar;"},
+    { NULL, NULL }
+  };
+
+  const char* statement_data[] = {
+    "=> 0",
+    "=>",
+    "() =>",
+    "=> {}",
+    ") => {}",
+    ", => {}",
+    "(,) => {}",
+    "return => {}",
+    "(a, if) => {}",
+    "(a * b) => {}",
+    "() => {'value': 42}",
+
+    // Check that the early return introduced in ParsePrimaryExpression
+    // does not accept stray closing parentheses.
+    ")",
+    ") => 0",
+    "foo[()]",
+    "()",
+
+    // Parameter lists with extra parens should be recognized as errors.
+    "(()) => 0",
+    "((x)) => 0",
+    "((x, y)) => 0",
+    "(x, (y)) => 0",
+    "((x, y, z)) => 0",
+    "(x, (y, z)) => 0",
+    "((x, y), z) => 0",
+

[marja, 2014/06/17 11:47:38]

Do any of the cases bump into the "is not a variable proxy" in
ParserTraits::ParameterListFromExpression()? I guess not? That would happen when
we expect a parameter name, but get some other kind of expression which is not a
parameter name, such as "13" or "foo ? bar : baz" or "foo + bar". Could you add
test cases for those?

+    NULL
+  };
+
+  RunParserSyncTest(context_data, statement_data, kError);
+}
+
+
+TEST(NoErrorsArrowFunctions) {
+  // Tests that parser and preparser accept valid arrow functions syntax.
+  i::FLAG_harmony_arrow_functions = true;
+
+  const char* context_data[][2] = {
+    {"", ";"},
+    {"bar ? (", ") : baz;"},
+    {"bar ? baz : (", ");"},
+    {"bar, ", ";"},
+    {"", ", bar;"},
+    { NULL, NULL }
+  };
+
+  const char* statement_data[] = {
+    "() => {}",
+    "() => { return 42 }",
+    "x => { return x; }",
+    "(x) => { return x; }",
+    "(x, y) => { return x + y; }",
+    "(x, y, z) => { return x + y + z; }",
+    "(x, y) => { x.a = y; }",
+    "() => 42",
+    "x => x",
+    "x => x * x",
+    "(x) => x",
+    "(x) => x * x",
+    "(x, y) => x + y",
+    "(x, y, z) => x, y, z",
+    "(x, y) => x.a = y",
+    "() => ({'value': 42})",
+    "x => y => x + y",
+    "(x, y) => (u, v) => x*u + y*v",
+    "(x, y) => z => z * (x + y)",
+    "x => (y, z) => z * (x + y)",
+    NULL
+  };
+
+  RunParserSyncTest(context_data, statement_data, kSuccess);
+}