[parser] Create arrow function scopes while parsing the head

This simplifies NextArrowFunctionInfo, allows us to Scope::Snapshot::Reparent
directly rather than moving it, and allows us to skip reparenting in the simple
parameter arrow function cases.

This CL additionally fixes arrow function name inferring.

Change-Id: Ie3e5ea778f3d7b84b2a10d4f4ff73931cfc9384a
Reviewed-on: https://chromium-review.googlesource.com/c/1386147Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58405}

src/ast/scopes.cc

@@ -888,11 +888,15 @@ void Scope::Snapshot::Reparent(DeclarationScope* new_parent) {
   outer_closure->locals_.Rewind(top_local_);
 
   // Move eval calls since Snapshot's creation into new_parent.
-  if (outer_scope_and_calls_eval_.GetPayload()) {
+  if (outer_scope_and_calls_eval_->scope_calls_eval_) {
     new_parent->scope_calls_eval_ = true;
     new_parent->inner_scope_calls_eval_ = true;
   }
 
+  // We are in the arrow function case. The calls eval we may have recorded
+  // is intended for the inner scope and we should simply restore the
+  // original "calls eval" flag of the outer scope.
+  RestoreEvalFlag();
   Clear();
 }
 

src/ast/scopes.h

@@ -147,24 +147,6 @@ class V8_EXPORT_PRIVATE Scope : public NON_EXPORTED_BASE(ZoneObject) {
           outer_scope_and_calls_eval_.GetPayload();
     }
 
-    Snapshot& operator=(Snapshot&& source) V8_NOEXCEPT {
-      outer_scope_and_calls_eval_.SetPointer(
-          source.outer_scope_and_calls_eval_.GetPointer());
-      outer_scope_and_calls_eval_.SetPayload(
-          outer_scope_and_calls_eval_->scope_calls_eval_);
-      top_inner_scope_ = source.top_inner_scope_;
-      top_unresolved_ = source.top_unresolved_;
-      top_local_ = source.top_local_;
-
-      // We are in the arrow function case. The calls eval we may have recorded
-      // is intended for the inner scope and we should simply restore the
-      // original "calls eval" flag of the outer scope.
-      source.RestoreEvalFlag();
-      source.Clear();
-
-      return *this;
-    }
-
     void Reparent(DeclarationScope* new_parent);
     bool IsCleared() const {
       return outer_scope_and_calls_eval_.GetPointer() == nullptr;

src/parsing/parser-base.h

@@ -271,8 +271,6 @@ class ParserBase {
     pointer_buffer_.reserve(128);
   }
 
-  ~ParserBase() { next_arrow_function_info_.scope_snapshot.Clear(); }
-
 #define ALLOW_ACCESSORS(name)                           \
   bool allow_##name() const { return allow_##name##_; } \
   void set_allow_##name(bool allow) { allow_##name##_ = allow; }
@@ -1386,7 +1384,6 @@ class ParserBase {
   // Preallocating the struct as part of the parser minimizes the cost of
   // supporting arrow functions on non-arrow expressions.
   struct NextArrowFunctionInfo {
-    Scope::Snapshot scope_snapshot;
     // `rewritable_length`: length of the destructuring_assignments_to_rewrite()
     // queue in the parent function state, prior to parsing of formal
     // parameters.  If the arrow function is lazy, any items added during formal
@@ -1395,19 +1392,15 @@ class ParserBase {
     Scanner::Location strict_parameter_error_location =
         Scanner::Location::invalid();
     MessageTemplate strict_parameter_error_message = MessageTemplate::kNone;
-    FunctionKind kind = FunctionKind::kArrowFunction;
-    bool has_simple_parameter_list = true;
+    DeclarationScope* scope = nullptr;
 
     bool HasInitialState() const {
-      return rewritable_length == -1 && scope_snapshot.IsCleared() &&
-             kind == FunctionKind::kArrowFunction && has_simple_parameter_list;
+      return rewritable_length == -1 && scope == nullptr;
     }
 
     void Reset() {
       rewritable_length = -1;
-      scope_snapshot.Clear();
-      kind = FunctionKind::kArrowFunction;
-      has_simple_parameter_list = true;
+      scope = nullptr;
       ClearStrictParameterError();
       DCHECK(HasInitialState());
     }
@@ -1663,8 +1656,7 @@ ParserBase<Impl>::ParsePrimaryExpression() {
   if (Token::IsAnyIdentifier(token)) {
     Consume(token);
 
-    IdentifierT name;
-    InferName infer = InferName::kYes;
+    FunctionKind kind = FunctionKind::kArrowFunction;
 
     if (V8_UNLIKELY(token == Token::ASYNC &&
                     !scanner()->HasLineTerminatorBeforeNext())) {
@@ -1675,28 +1667,28 @@ ParserBase<Impl>::ParsePrimaryExpression() {
       if (peek_any_identifier() && PeekAhead() == Token::ARROW) {
         token = Next();
         beg_pos = position();
-        next_arrow_function_info_.kind = FunctionKind::kAsyncArrowFunction;
-        infer = InferName::kNo;
+        kind = FunctionKind::kAsyncArrowFunction;
       }
     }
 
     if (V8_UNLIKELY(peek() == Token::ARROW)) {
+      next_arrow_function_info_.scope = NewFunctionScope(kind);
       ArrowHeadParsingScope parsing_scope(
-          impl(), next_arrow_function_info_.kind == FunctionKind::kArrowFunction
+          impl(), kind == FunctionKind::kArrowFunction
                       ? ExpressionScope::kMaybeArrowParameterDeclaration
                       : ExpressionScope::kMaybeAsyncArrowParameterDeclaration);
-      next_arrow_function_info_.scope_snapshot =
-          std::move(Scope::Snapshot(scope()));
       next_arrow_function_info_.rewritable_length = static_cast<int>(
           function_state_->destructuring_assignments_to_rewrite().size());
-      name = ParseAndClassifyIdentifier(token);
+      IdentifierT name = ParseAndClassifyIdentifier(token);
       ClassifyParameter(name, beg_pos, end_position());
       parsing_scope.ValidateDeclaration();
-    } else {
-      name = ParseAndClassifyIdentifier(token);
+      FunctionState function_state(&function_state_, &scope_,
+                                   next_arrow_function_info_.scope);
+      return impl()->ExpressionFromIdentifier(name, beg_pos, InferName::kNo);
     }
 
-    return impl()->ExpressionFromIdentifier(name, beg_pos, infer);
+    IdentifierT name = ParseAndClassifyIdentifier(token);
+    return impl()->ExpressionFromIdentifier(name, beg_pos);
   }
 
   if (Token::IsLiteral(token)) {
@@ -1721,17 +1713,18 @@ ParserBase<Impl>::ParsePrimaryExpression() {
 
     case Token::LPAREN: {
       Consume(Token::LPAREN);
-      Scope::Snapshot scope_snapshot(scope());
       int rewritable_length = static_cast<int>(
           function_state_->destructuring_assignments_to_rewrite().size());
       if (Check(Token::RPAREN)) {
         // ()=>x.  The continuation that consumes the => is in
         // ParseAssignmentExpressionCoverGrammar.
         if (peek() != Token::ARROW) ReportUnexpectedToken(Token::RPAREN);
-        next_arrow_function_info_.scope_snapshot = std::move(scope_snapshot);
+        next_arrow_function_info_.scope =
+            NewFunctionScope(FunctionKind::kArrowFunction);
         next_arrow_function_info_.rewritable_length = rewritable_length;
         return factory()->NewEmptyParentheses(beg_pos);
       }
+      Scope::Snapshot scope_snapshot(scope());
       ArrowHeadParsingScope maybe_arrow(
           impl(), ExpressionScope::kMaybeArrowParameterDeclaration);
       // Heuristically try to detect immediately called functions before
@@ -1746,9 +1739,12 @@ ParserBase<Impl>::ParsePrimaryExpression() {
       Expect(Token::RPAREN);
 
       if (peek() == Token::ARROW) {
-        next_arrow_function_info_.scope_snapshot = std::move(scope_snapshot);
-        next_arrow_function_info_.has_simple_parameter_list =
-            maybe_arrow.has_simple_parameter_list();
+        next_arrow_function_info_.scope =
+            NewFunctionScope(FunctionKind::kArrowFunction);
+        scope_snapshot.Reparent(next_arrow_function_info_.scope);
+        if (!maybe_arrow.has_simple_parameter_list()) {
+          next_arrow_function_info_.scope->SetHasNonSimpleParameters();
+        }
         next_arrow_function_info_.rewritable_length = rewritable_length;
         maybe_arrow.ValidateDeclaration();
       } else {
@@ -2619,7 +2615,6 @@ ParserBase<Impl>::ParseAssignmentExpressionCoverGrammar() {
   // Arrow functions.
   if (V8_UNLIKELY(op == Token::ARROW)) {
     Scanner::Location loc(lhs_beg_pos, end_position());
-    DeclarationScope* scope = NewFunctionScope(next_arrow_function_info_.kind);
 
     if (!impl()->IsIdentifier(expression) && !expression->is_parenthesized()) {
       impl()->ReportMessageAt(
@@ -2628,26 +2623,19 @@ ParserBase<Impl>::ParseAssignmentExpressionCoverGrammar() {
       return impl()->FailureExpression();
     }
 
-    // Because the arrow's parameters were parsed in the outer scope,
-    // we need to fix up the scope chain appropriately.
-    next_arrow_function_info_.scope_snapshot.Reparent(scope);
+    DeclarationScope* scope = next_arrow_function_info_.scope;
+    scope->set_start_position(lhs_beg_pos);
 
     FormalParametersT parameters(scope);
     parameters.set_strict_parameter_error(
         next_arrow_function_info_.strict_parameter_error_location,
         next_arrow_function_info_.strict_parameter_error_message);
-    if (!next_arrow_function_info_.has_simple_parameter_list) {
-      scope->SetHasNonSimpleParameters();
-      parameters.is_simple = false;
-    }
+    parameters.is_simple = scope->has_simple_parameters();
 
-    scope->set_start_position(lhs_beg_pos);
     impl()->DeclareArrowFunctionFormalParameters(&parameters, expression, loc);
 
     expression = ParseArrowFunctionLiteral(parameters);
 
-    fni_.Infer();
-
     return expression;
   }
 
@@ -2924,12 +2912,13 @@ ParserBase<Impl>::ParseUnaryOrPrefixExpression() {
 
   DCHECK(Token::IsCountOp(op));
 
-  if (V8_UNLIKELY(!IsValidReferenceExpression(expression))) {
+  if (V8_LIKELY(IsValidReferenceExpression(expression))) {
+    if (peek() != Token::ARROW) impl()->MarkExpressionAsAssigned(expression);
+  } else {
     expression = RewriteInvalidReferenceExpression(
         expression, expression_position, end_position(),
         MessageTemplate::kInvalidLhsInPrefixOp);
   }
-  impl()->MarkExpressionAsAssigned(expression);
 
   return factory()->NewCountOperation(op, true /* prefix */, expression,
                                       position());
@@ -3038,15 +3027,17 @@ ParserBase<Impl>::ParseLeftHandSideContinuation(ExpressionT result) {
     if (V8_LIKELY(peek() == Token::ARROW)) {
       maybe_arrow.ValidateDeclaration();
       fni_.RemoveAsyncKeywordFromEnd();
-      next_arrow_function_info_.kind = FunctionKind::kAsyncArrowFunction;
-      next_arrow_function_info_.scope_snapshot = std::move(scope_snapshot);
+      next_arrow_function_info_.scope =
+          NewFunctionScope(FunctionKind::kAsyncArrowFunction);
+      scope_snapshot.Reparent(next_arrow_function_info_.scope);
       next_arrow_function_info_.rewritable_length = rewritable_length;
       // async () => ...
       if (!args.length()) return factory()->NewEmptyParentheses(pos);
       // async ( Arguments ) => ...
       ExpressionT result = impl()->ExpressionListToExpression(args);
-      next_arrow_function_info_.has_simple_parameter_list =
-          maybe_arrow.has_simple_parameter_list();
+      if (!maybe_arrow.has_simple_parameter_list()) {
+        next_arrow_function_info_.scope->SetHasNonSimpleParameters();
+      }
       result->mark_parenthesized();
       return result;
     }
@@ -4081,10 +4072,13 @@ ParserBase<Impl>::ParseArrowFunctionLiteral(
           // In case we did not sucessfully preparse the function because of an
           // unidentified error we do a full reparse to return the error.
           ExpressionT expression = ParseConditionalExpression();
-          Scanner::Location loc(scope()->start_position(), end_position());
-          FormalParametersT parameters(formal_parameters.scope);
-          parameters.is_simple =
-              next_arrow_function_info_.has_simple_parameter_list;
+          DeclarationScope* function_scope = next_arrow_function_info_.scope;
+          FunctionState function_state(&function_state_, &scope_,
+                                       function_scope);
+          Scanner::Location loc(function_scope->start_position(),
+                                end_position());
+          FormalParametersT parameters(function_scope);
+          parameters.is_simple = function_scope->has_simple_parameters();
           impl()->DeclareArrowFunctionFormalParameters(&parameters, expression,
                                                        loc);
           next_arrow_function_info_.Reset();

test/inspector/debugger/async-chains-expected.txt

@@ -42,7 +42,7 @@ userFunction (test.js:1:36)
 -- inner async --
 runWithRegular (utils.js:2:12)
 inner (test.js:2:28)
-runWithRegular (utils.js:21:4)
+(anonymous) (utils.js:21:4)
   <external stack>
 
 EmptyName
@@ -88,7 +88,7 @@ userFunction (test.js:1:36)
 -- <empty> --
 runWithEmptyName (utils.js:6:12)
 inner (test.js:2:28)
-runWithRegular (utils.js:21:4)
+(anonymous) (utils.js:21:4)
   <external stack>
 
 EmptyStack
@@ -147,6 +147,6 @@ userFunction (test.js:1:36)
 
 External
 userFunction (test.js:1:36)
-runWithRegular (utils.js:21:4)
+(anonymous) (utils.js:21:4)
   <external stack>
 

test/inspector/debugger/async-stack-created-frame-expected.txt

@@ -80,11 +80,11 @@ thenableJob2 (test.js:64:57)
 
 Running test: testSetTimeouts
 foo1 (test.js:10:2)
-setTimeout (test.js:72:25)
+(anonymous) (test.js:72:25)
 -- setTimeout --
-setTimeout (test.js:72:6)
+(anonymous) (test.js:72:6)
 -- setTimeout --
-setTimeout (test.js:71:4)
+(anonymous) (test.js:71:4)
 -- setTimeout --
 setTimeouts (test.js:70:2)
 (anonymous) (expr.js:0:0)

test/inspector/debugger/async-stack-for-promise-expected.txt

@@ -101,11 +101,11 @@ foo1 (test.js:156:4)
 complex (test.js:202:5)
 (anonymous) (testComplex.js:0:0)
 
-p.then (test.js:207:8)
+(anonymous) (test.js:207:8)
 -- Promise.then --
-p.then (test.js:206:8)
+(anonymous) (test.js:206:8)
 -- Promise.then --
-setTimeout (test.js:205:6)
+(anonymous) (test.js:205:6)
 -- setTimeout --
 complex (test.js:204:2)
 (anonymous) (testComplex.js:0:0)

test/inspector/debugger/async-stack-load-more-expected.txt

 Tests super long async stacks.
-callWithAsyncStack (expr.js:0:26)
+(anonymous) (expr.js:0:26)
 callWithAsyncStack (utils.js:3:4)
 call1 (wrapper.js:0:20)
 --Promise.then--

test/inspector/debugger/break-locations-await-expected.txt

@@ -213,12 +213,12 @@ f1 (test.js:4:36)
     return await Promise.resolve(2);#
   }
 
-f1.then.x (test.js:10:27)
+(anonymous) (test.js:10:27)
     await f1();
     await f1().then(x => x #* 2);
     await [1].map(x => Promise.resolve(x))[0];
 
-f1.then.x (test.js:10:30)
+(anonymous) (test.js:10:30)
     await f1();
     await f1().then(x => x * 2#);
     await [1].map(x => Promise.resolve(x))[0];
@@ -228,13 +228,13 @@ f2 (test.js:11:4)
     #await [1].map(x => Promise.resolve(x))[0];
     await Promise.resolve().then(x => x * 2);
 
-map.x (test.js:11:31)
+(anonymous) (test.js:11:31)
 f2 (test.js:11:14)
     await f1().then(x => x * 2);
     await [1].map(x => Promise.#resolve(x))[0];
     await Promise.resolve().then(x => x * 2);
 
-map.x (test.js:11:41)
+(anonymous) (test.js:11:41)
 f2 (test.js:11:14)
     await f1().then(x => x * 2);
     await [1].map(x => Promise.resolve(x)#)[0];

test/inspector/debugger/break-locations-var-init-optimized-expected.txt

@@ -153,32 +153,32 @@ asyncF (test.js:17:13)
     return r;#
   })();
 
-Promise.resolve.then.then.x (test.js:4:64)
+(anonymous) (test.js:4:64)
   var arr1 = [1];
   var promise = Promise.resolve(1).then(x => x * 2).then(x => x #/ 2);
   Promise.resolve(1).then(x => x * 2).then(x => x / 2);
 
-Promise.resolve.then.then.x (test.js:4:67)
+(anonymous) (test.js:4:67)
   var arr1 = [1];
   var promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2#);
   Promise.resolve(1).then(x => x * 2).then(x => x / 2);
 
-Promise.resolve.then.then.x (test.js:5:50)
+(anonymous) (test.js:5:50)
   var promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2);
   Promise.resolve(1).then(x => x * 2).then(x => x #/ 2);
   promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2);
 
-Promise.resolve.then.then.x (test.js:5:53)
+(anonymous) (test.js:5:53)
   var promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2);
   Promise.resolve(1).then(x => x * 2).then(x => x / 2#);
   promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2);
 
-Promise.resolve.then.then.x (test.js:6:60)
+(anonymous) (test.js:6:60)
   Promise.resolve(1).then(x => x * 2).then(x => x / 2);
   promise = Promise.resolve(1).then(x => x * 2).then(x => x #/ 2);
   var a = 1;
 
-Promise.resolve.then.then.x (test.js:6:63)
+(anonymous) (test.js:6:63)
   Promise.resolve(1).then(x => x * 2).then(x => x / 2);
   promise = Promise.resolve(1).then(x => x * 2).then(x => x / 2#);
   var a = 1;

test/inspector/debugger/get-possible-breakpoints-expected.txt

@@ -81,10 +81,10 @@ function foo2() { Promise.resolve().then(() => 42) }
 paused in foo1
 function foo1() { Promise.resolve().then(() => 42) ^}
 function foo2() { Promise.resolve().then(() => 42) }
-paused in Promise.resolve.then
+paused in 
 function foo1() { Promise.resolve().then(() => ^42) }
 function foo2() { Promise.resolve().then(() => 42) }
-paused in Promise.resolve.then
+paused in 
 function foo1() { Promise.resolve().then(() => 42^) }
 function foo2() { Promise.resolve().then(() => 42) }
 
@@ -148,22 +148,22 @@ debugger; function foo3() { Promise.resolve().then(() => 42) }
 function foo4() { Promise.resolve().then(() => 42) };
 foo3();
 foo4();^
-paused in Promise.resolve.then
+paused in 
 debugger; function foo3() { Promise.resolve().then(() => ^42) }
 function foo4() { Promise.resolve().then(() => 42) };
 foo3();
 foo4();
-paused in Promise.resolve.then
+paused in 
 debugger; function foo3() { Promise.resolve().then(() => 42^) }
 function foo4() { Promise.resolve().then(() => 42) };
 foo3();
 foo4();
-paused in Promise.resolve.then
+paused in 
 debugger; function foo3() { Promise.resolve().then(() => 42) }
 function foo4() { Promise.resolve().then(() => ^42) };
 foo3();
 foo4();
-paused in Promise.resolve.then
+paused in 
 debugger; function foo3() { Promise.resolve().then(() => 42) }
 function foo4() { Promise.resolve().then(() => 42^) };
 foo3();
@@ -247,19 +247,19 @@ paused in foo6
 function foo5() { Promise.resolve().then(() => 42) }
 function foo6() { Promise.resolve().then(() => 42) ^}
 
-paused in Promise.resolve.then
+paused in 
 function foo5() { Promise.resolve().then(() => ^42) }
 function foo6() { Promise.resolve().then(() => 42) }
 
-paused in Promise.resolve.then
+paused in 
 function foo5() { Promise.resolve().then(() => 42^) }
 function foo6() { Promise.resolve().then(() => 42) }
 
-paused in Promise.resolve.then
+paused in 
 function foo5() { Promise.resolve().then(() => 42) }
 function foo6() { Promise.resolve().then(() => ^42) }
 
-paused in Promise.resolve.then
+paused in 
 function foo5() { Promise.resolve().then(() => 42) }
 function foo6() { Promise.resolve().then(() => 42^) }
 

test/inspector/debugger/max-async-call-chain-depth-expected.txt

@@ -46,7 +46,7 @@ Running test: testConsoleTraceWithEmptySync
     callFrames : [
         [0] : {
             columnNumber : 66
-            functionName : Promise.then
+            functionName : 
             lineNumber : 0
             scriptId : <scriptId>
             url : 

test/inspector/debugger/promise-chain-when-limit-hit-expected.txt

@@ -23,7 +23,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -40,7 +40,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -58,7 +58,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 
@@ -114,7 +114,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -131,7 +131,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -149,7 +149,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 
@@ -205,7 +205,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -222,7 +222,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -240,7 +240,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 
@@ -296,7 +296,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -313,7 +313,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -331,7 +331,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 
@@ -387,7 +387,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -404,7 +404,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -422,7 +422,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 
@@ -478,7 +478,7 @@ Run expression 'console.trace()' with async chain len: 3
                 }
                 [1] : {
                     columnNumber : 33
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 5
                     scriptId : <scriptId>
                     url : 
@@ -495,7 +495,7 @@ Run expression 'console.trace()' with async chain len: 3
                     }
                     [1] : {
                         columnNumber : 33
-                        functionName : Promise.resolve.then
+                        functionName : 
                         lineNumber : 5
                         scriptId : <scriptId>
                         url : 
@@ -513,7 +513,7 @@ Run expression 'console.trace()' with async chain len: 3
                         }
                         [1] : {
                             columnNumber : 33
-                            functionName : Promise.resolve.then
+                            functionName : 
                             lineNumber : 5
                             scriptId : <scriptId>
                             url : 

test/inspector/debugger/script-origin-stack-expected.txt

@@ -16,7 +16,7 @@ Debugger.scriptParsed.stackTrace should contain only one frame
             callFrames : [
                 [0] : {
                     columnNumber : 17
-                    functionName : setTimeout
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 

test/inspector/debugger/step-into-break-on-async-call-expected.txt

@@ -3,11 +3,11 @@ Test for Debugger.stepInto with breakOnAsyncCall.
 Running test: testSetTimeout
 (anonymous) (test.js:0:0)
 asyncCallStackTraceId is set
-setTimeout (test.js:0:17)
+(anonymous) (test.js:0:17)
 asyncCallStackTraceId is empty
 
 Running test: testPromiseThen
 (anonymous) (test.js:0:2)
 asyncCallStackTraceId is set
-p.then (test.js:0:13)
+(anonymous) (test.js:0:13)
 asyncCallStackTraceId is empty

test/inspector/runtime/evaluate-run-microtasks-expected.txt

@@ -14,7 +14,7 @@ Tests that microtasks run before the Runtime.evaluate response is sent
             callFrames : [
                 [0] : {
                     columnNumber : 37
-                    functionName : Promise.resolve.then
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 

test/inspector/runtime/exception-thrown-expected.txt

@@ -6,16 +6,16 @@ Check that exceptionThrown is supported by test runner.
             columnNumber : 2
             exception : {
                 className : Error
-                description : Error     at setTimeout (<anonymous>:2:9)
+                description : Error     at <anonymous>:2:9
                 objectId : <objectId>
                 preview : {
-                    description : Error     at setTimeout (<anonymous>:2:9)
+                    description : Error     at <anonymous>:2:9
                     overflow : false
                     properties : [
                         [0] : {
                             name : stack
                             type : string
-                            value : Error     at setTimeout (<anonymous>:2:9)
+                            value : Error     at <anonymous>:2:9
                         }
                     ]
                     subtype : error
@@ -31,7 +31,7 @@ Check that exceptionThrown is supported by test runner.
                 callFrames : [
                     [0] : {
                         columnNumber : 8
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 1
                         scriptId : <scriptId>
                         url : 
@@ -99,7 +99,7 @@ Check that exceptionThrown is supported by test runner.
                 callFrames : [
                     [0] : {
                         columnNumber : 2
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 1
                         scriptId : <scriptId>
                         url : 

test/inspector/sessions/runtime-console-api-called-expected.txt

@@ -125,7 +125,7 @@ From session 1
             callFrames : [
                 [0] : {
                     columnNumber : 25
-                    functionName : setTimeout
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 
@@ -151,7 +151,7 @@ From session 2
             callFrames : [
                 [0] : {
                     columnNumber : 25
-                    functionName : setTimeout
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 
@@ -178,7 +178,7 @@ From session 1
             callFrames : [
                 [0] : {
                     columnNumber : 25
-                    functionName : setTimeout
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 
@@ -204,7 +204,7 @@ From session 2
             callFrames : [
                 [0] : {
                     columnNumber : 25
-                    functionName : setTimeout
+                    functionName : 
                     lineNumber : 0
                     scriptId : <scriptId>
                     url : 

test/inspector/sessions/runtime-evaluate-exception-expected.txt

@@ -19,7 +19,7 @@ From session 1
                 callFrames : [
                     [0] : {
                         columnNumber : 19
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -48,7 +48,7 @@ From session 2
                 callFrames : [
                     [0] : {
                         columnNumber : 19
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -78,7 +78,7 @@ From session 1
                 callFrames : [
                     [0] : {
                         columnNumber : 19
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -107,7 +107,7 @@ From session 2
                 callFrames : [
                     [0] : {
                         columnNumber : 19
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -137,7 +137,7 @@ From session 1
                 callFrames : [
                     [0] : {
                         columnNumber : 40
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -166,7 +166,7 @@ From session 2
                 callFrames : [
                     [0] : {
                         columnNumber : 40
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -215,7 +215,7 @@ From session 1
                 callFrames : [
                     [0] : {
                         columnNumber : 40
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 
@@ -244,7 +244,7 @@ From session 2
                 callFrames : [
                     [0] : {
                         columnNumber : 40
-                        functionName : setTimeout
+                        functionName : 
                         lineNumber : 0
                         scriptId : <scriptId>
                         url : 

test/message/mjsunit/fail/assert-promise-result-rejects-with-throw-empty.out

@@ -7,4 +7,4 @@ Error
 
 Error: Reject with callback
     at concatenateErrors (test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER})
-    at _ (test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER})
+    at test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER}

test/message/mjsunit/fail/assert-promise-result-rejects.out

@@ -6,7 +6,7 @@ Error
     at *%(basename)s:9:1
 
 Error: Error in reject handler
-    at _ *%(basename)s:11:17)
-    at promise.then.result (test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER})
+    at *%(basename)s:11:17
+    at test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER}
 
 

test/message/mjsunit/fail/assert-promise-result-resolves.out

@@ -6,8 +6,8 @@ Error
     at *%(basename)s:9:1
 
 Error: Error in resolve handler
-    at _ *%(basename)s:10:39)
-    at promise.then.result (test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER})
+    at *%(basename)s:10:39
+    at test/mjsunit/mjsunit.js:{NUMBER}:{NUMBER}
 
 
 

test/message/wasm-function-name-async.out

 RuntimeError: unreachable
     at main (wasm-function[0]:1)
-    at pair (*%(basename)s:16:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at *%(basename)s:16:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-function-name-streaming.out

 RuntimeError: unreachable
     at main (wasm-function[0]:1)
-    at pair (test/message/wasm-function-name-async.js:16:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at test/message/wasm-function-name-async.js:16:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-module-and-function-name-async.out

 RuntimeError: unreachable
     at test-module.main (wasm-function[0]:1)
-    at pair (*%(basename)s:17:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at *%(basename)s:17:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-module-and-function-name-streaming.out

 RuntimeError: unreachable
     at test-module.main (wasm-function[0]:1)
-    at pair (test/message/wasm-module-and-function-name-async.js:17:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at test/message/wasm-module-and-function-name-async.js:17:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-module-name-async.out

 RuntimeError: unreachable
     at test-module (wasm-function[0]:1)
-    at pair (*%(basename)s:19:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at *%(basename)s:19:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-module-name-streaming.out

 RuntimeError: unreachable
     at test-module (wasm-function[0]:1)
-    at pair (test/message/wasm-module-name-async.js:19:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at test/message/wasm-module-name-async.js:19:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-no-name-async.out

 RuntimeError: unreachable
     at wasm-function[0]:1
-    at pair (*%(basename)s:18:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at *%(basename)s:18:27
+    at test/mjsunit/mjsunit.js:*

test/message/wasm-no-name-streaming.out

 RuntimeError: unreachable
     at wasm-function[0]:1
-    at pair (test/message/wasm-no-name-async.js:18:27)
-    at promise.then.result (test/mjsunit/mjsunit.js:*)
+    at test/message/wasm-no-name-async.js:18:27
+    at test/mjsunit/mjsunit.js:*

test/mjsunit/es8/async-function-stacktrace.js

@@ -81,21 +81,19 @@ async function runTests() {
     try { await reject(); } catch (e) { throw new Error("FAIL"); }
   } }).c4, ["c4"]);
 
-  // TODO(caitp): We should infer anonymous async functions as the empty
-  // string, not as the name of a function they're passed as a parameter to.
   await test(async x => { throw new Error("FAIL") },
-             ["test", "test", "runTests"]);
+             ["test", "runTests"]);
   await test(async() => { throw new Error("FAIL") },
-             ["test", "test", "runTests"]);
+             ["test", "runTests"]);
   await test(async(a) => { throw new Error("FAIL") },
-             ["test", "test", "runTests"]);
+             ["test", "runTests"]);
   await test(async(a, b) => { throw new Error("FAIL") },
-             ["test", "test", "runTests"]);
+             ["test", "runTests"]);
 
-  await test(async x => { await 1; throw new Error("FAIL") }, ["test"]);
-  await test(async() => { await 1; throw new Error("FAIL") }, ["test"]);
-  await test(async(a) => { await 1; throw new Error("FAIL") }, ["test"]);
-  await test(async(a, b) => { await 1; throw new Error("FAIL") }, ["test"]);
+  await test(async x => { await 1; throw new Error("FAIL") }, []);
+  await test(async() => { await 1; throw new Error("FAIL") }, []);
+  await test(async(a) => { await 1; throw new Error("FAIL") }, []);
+  await test(async(a, b) => { await 1; throw new Error("FAIL") }, []);
 
   await test(async x => {
     await 1;
@@ -104,7 +102,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async() => {
     await 1;
@@ -113,7 +111,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async(a) => {
     await 1;
@@ -122,7 +120,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async(a, b) => {
     await 1;
@@ -131,7 +129,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async x => {
     await 1;
@@ -140,7 +138,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async() => {
     await 1;
@@ -149,7 +147,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async(a) => {
     await 1;
@@ -158,7 +156,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 
   await test(async(a, b) => {
     await 1;
@@ -167,7 +165,7 @@ async function runTests() {
     } catch (e) {
       throw new Error("FAIL");
     }
-  }, ["test"]);
+  }, []);
 }
 
 runTests().catch(e => {