[es8] Throw SyntaxError when tail call expressions occur in non-strict mode.

BUG=v8:4915
LOG=N

Review-Url: https://codereview.chromium.org/1955393002
Cr-Commit-Position: refs/heads/master@{#36105}

src/messages.h

@@ -446,6 +446,8 @@ class CallSite {
   T(UnexpectedReserved, "Unexpected reserved word")                            \
   T(UnexpectedStrictReserved, "Unexpected strict mode reserved word")          \
   T(UnexpectedSuper, "'super' keyword unexpected here")                        \
+  T(UnexpectedSloppyTailCall,                                                  \
+    "Tail call expressions are not allowed in non-strict mode")                \
   T(UnexpectedNewTarget, "new.target expression is not allowed here")          \
   T(UnexpectedTailCall, "Tail call expression is not allowed here")            \
   T(UnexpectedTailCallInCatchBlock,                                            \

src/parsing/parser-base.h

@@ -2228,6 +2228,17 @@ ParserBase<Traits>::ParseTailCallExpression(ExpressionClassifier* classifier,
   CheckNoTailCallExpressions(classifier, CHECK_OK);
 
   Scanner::Location loc(pos, scanner()->location().end_pos);
+  if (!expression->IsCall()) {
+    Scanner::Location sub_loc(sub_expression_pos, loc.end_pos);
+    ReportMessageAt(sub_loc, MessageTemplate::kUnexpectedInsideTailCall);
+    *ok = false;
+    return Traits::EmptyExpression();
+  }
+  if (!is_strict(language_mode())) {
+    ReportMessageAt(loc, MessageTemplate::kUnexpectedSloppyTailCall);
+    *ok = false;
+    return Traits::EmptyExpression();
+  }
   ReturnExprContext return_expr_context =
       function_state_->return_expr_context();
   if (return_expr_context != ReturnExprContext::kInsideValidReturnStatement) {
@@ -2250,12 +2261,6 @@ ParserBase<Traits>::ParseTailCallExpression(ExpressionClassifier* classifier,
     *ok = false;
     return Traits::EmptyExpression();
   }
-  if (!expression->IsCall()) {
-    Scanner::Location sub_loc(sub_expression_pos, loc.end_pos);
-    ReportMessageAt(sub_loc, MessageTemplate::kUnexpectedInsideTailCall);
-    *ok = false;
-    return Traits::EmptyExpression();
-  }
   classifier->RecordTailCallExpressionError(
       loc, MessageTemplate::kUnexpectedTailCall);
   function_state_->AddExpressionInTailPosition(expression, loc);

test/message/syntactic-tail-call-in-binop-lhs.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-binop-lhs.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return   continue f()   - a ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-binop-rhs.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-binop-rhs.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return b + continue f()  ;
              ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-comma.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-comma.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return 1, 2, 3,   continue f() , 4  ;
                     ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-extends.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function g() {
   return class A extends continue f() {};

test/message/syntactic-tail-call-in-extends.out

-*%(basename)s:8: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:9: SyntaxError: Tail call expression is not allowed here
   return class A extends continue f() {};
                          ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-for-in.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-for-in.out

-*%(basename)s:13: SyntaxError: Tail call expression in for-in/of body
+*%(basename)s:14: SyntaxError: Tail call expression in for-in/of body
     return continue f()  ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression in for-in/of body

test/message/syntactic-tail-call-in-for-of.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-for-of.out

-*%(basename)s:13: SyntaxError: Tail call expression in for-in/of body
+*%(basename)s:14: SyntaxError: Tail call expression in for-in/of body
     return continue f()  ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression in for-in/of body

test/message/syntactic-tail-call-in-logical-and.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-logical-and.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return   continue f()   && a ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-logical-or.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-logical-or.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return   continue f()   || a ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-subclass.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function g() {
   class A {};

test/message/syntactic-tail-call-in-subclass.out

-*%(basename)s:11: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
       return continue f() ;
              ^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-in-try-catch-finally.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-try-catch-finally.out

-*%(basename)s:15: SyntaxError: Tail call expression in catch block when finally block is also present
+*%(basename)s:16: SyntaxError: Tail call expression in catch block when finally block is also present
     return continue f()  ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression in catch block when finally block is also present

test/message/syntactic-tail-call-in-try-try-catch-finally.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-try-try-catch-finally.out

-*%(basename)s:16: SyntaxError: Tail call expression in try block
+*%(basename)s:17: SyntaxError: Tail call expression in try block
       return continue f()  ;
              ^^^^^^^^^^^^
 SyntaxError: Tail call expression in try block

test/message/syntactic-tail-call-in-try.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-in-try.out

-*%(basename)s:13: SyntaxError: Tail call expression in try block
+*%(basename)s:14: SyntaxError: Tail call expression in try block
     return continue f()  ;
            ^^^^^^^^^^^^
 SyntaxError: Tail call expression in try block

test/message/syntactic-tail-call-inside-member-expr.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-inside-member-expr.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   return (continue  f(1)) (2) ;
           ^^^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/message/syntactic-tail-call-of-identifier.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function g(x) {
   return continue   x  ;

test/message/syntactic-tail-call-of-identifier.out

-*%(basename)s:8: SyntaxError: Unexpected expression inside tail call
+*%(basename)s:9: SyntaxError: Unexpected expression inside tail call
   return continue   x  ;
                     ^
 SyntaxError: Unexpected expression inside tail call

test/message/syntactic-tail-call-sloppy.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-explicit-tailcalls
+
+function g() {
+  return  continue  f()  ;
+}

test/message/syntactic-tail-call-sloppy.out

+*%(basename)s:8: SyntaxError: Tail call expressions are not allowed in non-strict mode
+  return  continue  f()  ;
+          ^^^^^^^^^^^^^
+SyntaxError: Tail call expressions are not allowed in non-strict mode

test/message/syntactic-tail-call-without-return.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --harmony-explicit-tailcalls
+"use strict";
 
 function f() {
   return 1;

test/message/syntactic-tail-call-without-return.out

-*%(basename)s:12: SyntaxError: Tail call expression is not allowed here
+*%(basename)s:13: SyntaxError: Tail call expression is not allowed here
   var x =  continue  f()  ;
            ^^^^^^^^^^^^^
 SyntaxError: Tail call expression is not allowed here

test/mjsunit/es6/tail-call.js

@@ -261,9 +261,8 @@ function f_153(expected_call_stack, a) {
   }
   %NeverOptimizeFunction(g);
 
-  var context = 10;
   function f(v) {
-    return g(context);
+    return g();
   }
   %SetForceInlineFlag(f);
 

test/mjsunit/es8/syntactic-tail-call-parsing-sloppy.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-explicit-tailcalls
+// Flags: --harmony-do-expressions
+
+var SyntaxErrorTests = [
+  { msg: "Unexpected expression inside tail call",
+    tests: [
+      { src: `()=>{ return continue  foo ; }`,
+        err: `                       ^^^`,
+      },
+      { src: `()=>{ return  continue 42 ; }`,
+        err: `                       ^^`,
+      },
+      { src: `()=>{ return  continue   new foo ()  ; }`,
+        err: `                         ^^^^^^^^^^`,
+      },
+      { src: `()=>{ loop: return  continue  loop ; }`,
+        err: `                              ^^^^`,
+      },
+      { src: `class A { foo() { return  continue   super.x ; } }`,
+        err: `                                     ^^^^^^^`,
+      },
+      { src: `()=>{ return  continue  this  ; }`,
+        err: `                        ^^^^`,
+      },
+      { src: `()=>{ return  continue class A {} ; }`,
+        err: `                       ^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue class A extends B {} ; }`,
+        err: `                       ^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue function A() { } ; }`,
+        err: `                       ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue { a: b, c: d} ; }`,
+        err: `                       ^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue function* Gen() { yield 1; } ; }`,
+        err: `                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `function A() { return  continue new.target ; }`,
+        err: `                                ^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue () ; }`,
+        err: `                       ^^`,
+      },
+      { src: `()=>{ return  continue ( 42 ) ; }`,
+        err: `                       ^^^^^^`,
+      },
+      { src: "()=>{ return continue `123 ${foo} 34lk` ;  }",
+        err: `                      ^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue do { x ? foo() : bar() ; } }`,
+        err: `                      ^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+    ],
+  },
+  { msg: "Tail call expression is not allowed here",
+    tests: [
+      { src: `class A {}; class B extends A { constructor() { return continue foo () ; } }`,
+        err: `                                                       ^^^^^^^^^^^^^^^`,
+      },
+      { src: `class A extends continue f () {}; }`,
+        err: `                ^^^^^^^^^^^^^`,
+      },
+    ],
+  },
+  { msg: "Tail call expressions are not allowed in non-strict mode",
+    tests: [
+      { src: `()=>{ return  continue continue continue b()  ; }`,
+        err: `                                ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return  continue ( continue b() ) ; }`,
+        err: `                         ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return   continue  f()   - a ; }`,
+        err: `               ^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return b + continue   f()  ; }`,
+        err: `                 ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return 1, 2, 3,   continue  f() , 4  ; }`,
+        err: `                        ^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ var x =  continue  f ( ) ; }`,
+        err: `               ^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return   continue f () ? 1 : 2 ; }`,
+        err: `               ^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return (1, 2, 3, continue f()), 4; }`,
+        err: `                       ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return [1, 2, continue f() ] ;  }`,
+        err: `                    ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return [1, 2, ... continue f() ] ;  }`,
+        err: `                        ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return [1, 2, continue f(), 3 ] ;  }`,
+        err: `                    ^^^^^^^^^^^^`,
+      },
+      { src: "()=>{ return `123 ${a} ${ continue foo ( ) } 34lk` ;  }",
+        err: `                          ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return g( 1, 2, continue f() ); }`,
+        err: `                      ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue f() || a; }`,
+        err: `             ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a || b || c || continue f() || d; }`,
+        err: `                            ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a && b && c && continue f() && d; }`,
+        err: `                            ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a && b || c && continue f() ? d : e; }`,
+        err: `                            ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a ? b : c && continue f() && d || e; }`,
+        err: `                          ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue foo() instanceof bar ; }`,
+        err: `             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return bar instanceof continue foo() ; }`,
+        err: `                            ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue foo() in bar ; }`,
+        err: `             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return bar in continue foo() ; }`,
+        err: `                    ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ function* G() { yield continue foo(); } }`,
+        err: `                            ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ (1, 2, 3, continue f() ) => {} }`,
+        err: `                ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ (... continue f()) => {}  }`,
+        err: `           ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ (a, b, c, ... continue f() ) => {}  }`,
+        err: `                    ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a <= continue f(); }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return b > continue f(); }`,
+        err: `                 ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a << continue f(); }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return b >> continue f(); }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return c >>> continue f(); }`,
+        err: `                   ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue f() = a ; }`,
+        err: `             ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a = continue f() ; }`,
+        err: `                 ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a += continue f(); }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a ** continue f() ; }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return delete continue foo() ; }`,
+        err: `                    ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ typeof continue foo()  ; }`,
+        err: `             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return ~ continue foo() ; }`,
+        err: `               ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return void  continue foo() ; }`,
+        err: `                   ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return !continue foo() ; }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return -continue foo() ; }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return +continue foo() ; }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return ++ continue f( ) ; }`,
+        err: `                ^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue f()  ++; }`,
+        err: `             ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue f() --; }`,
+        err: `             ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return (continue foo()) () ;  }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ for (var i = continue foo(); i < 10; i++) bar(); }`,
+        err: `                   ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ for (var i = 0; i < continue foo(); i++) bar(); }`,
+        err: `                          ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ for (var i = 0; i < 10; continue foo()) bar(); }`,
+        err: `                              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ if (continue foo()) bar(); }`,
+        err: `          ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ while (continue foo()) bar(); }`,
+        err: `             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ do { smth; } while (continue foo()) ; }`,
+        err: `                          ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ throw continue foo() ; }`,
+        err: `            ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ switch (continue foo()) { case 1: break; } ; }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ with (continue foo()) { smth; } }`,
+        err: `            ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ let x = continue foo() }`,
+        err: `              ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ const c = continue  foo() }`,
+        err: `                ^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ try { return  continue   f ( ) ; } catch(e) {} }`,
+        err: `                    ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ try { try { smth; } catch(e) { return  continue  f( ) ; } }`,
+        err: `                                             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ try { try { smth; } catch(e) { return  continue  f( ) ; } } finally { bla; } }`,
+        err: `                                             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ try { smth; } catch(e) { return  continue   f ( ) ; } finally { blah; } }`,
+        err: `                                       ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ try { smth; } catch(e) { try { smth; } catch (e) { return  continue   f ( ) ; } } finally { blah; } }`,
+        err: `                                                                 ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ for (var v in {a:0}) { return continue  foo () ; } }`,
+        err: `                                    ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ for (var v of [1, 2, 3]) { return continue  foo () ; } }`,
+        err: `                                        ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue  a.b.c.foo () ; }`,
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue  a().b.c().d.foo () ; }`,
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue  foo (1)(2)(3, 4) ; }`,
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return ( continue b() ) ; }`,
+        err: `               ^^^^^^^^^^^^`,
+      },
+      { src: "()=>{ return continue bar`ab cd ef` ; }",
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: "()=>{ return continue bar`ab ${cd} ef` ; }",
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a || continue f() ; }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a && continue f() ; }`,
+        err: `                  ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a , continue f() ; }`,
+        err: `                 ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ function* G() { return continue foo(); } }`,
+        err: `                             ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ function B() { return continue new.target() ; } }`,
+        err: `                            ^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue do { x ? foo() : bar() ; }() }`,
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return continue (do { x ? foo() : bar() ; })() }`,
+        err: `             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return do { 1, continue foo() } }`,
+        err: `                     ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return do { x ? continue foo() : y } }`,
+        err: `                      ^^^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a || (b && continue c()); }`,
+        err: `                        ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a && (b || continue c()); }`,
+        err: `                        ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return a || (b ? c : continue d()); }`,
+        err: `                           ^^^^^^^^^^^^`,
+      },
+      { src: `()=>{ return 1, 2, 3, a || (b ? c : continue d()); }`,
+        err: `                                    ^^^^^^^^^^^^`,
+      },
+      { src: `()=> continue  (foo ()) ;`,
+        err: `     ^^^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=> a || continue  foo () ;`,
+        err: `          ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=> a && continue  foo () ;`,
+        err: `          ^^^^^^^^^^^^^^^^`,
+      },
+      { src: `()=> a ? continue  foo () : b;`,
+        err: `         ^^^^^^^^^^^^^^^^`,
+      },
+    ],
+  },
+  { msg: "Undefined label 'foo'",
+    tests: [
+      { src: `()=>{ continue  foo () ; }`,
+        err: `                ^^^`,
+      },
+    ],
+  },
+];
+
+
+// Should parse successfully.
+var NoErrorTests = [
+  `()=>{ class A { foo() { return continue super.f() ; } } }`,
+  `()=>{ class A { foo() { return continue f() ; } } }`,
+  `()=>{ class A { foo() { return a || continue f() ; } } }`,
+  `()=>{ class A { foo() { return b && continue f() ; } } }`,
+];
+
+
+(function() {
+  for (var test_set of SyntaxErrorTests) {
+    var expected_message = "SyntaxError: " + test_set.msg;
+    for (var test of test_set.tests) {
+      var passed = true;
+      var e = null;
+      try {
+        Realm.eval(0, test.src);
+      } catch (ee) {
+        e = ee;
+      }
+      print("=======================================");
+      print("Expected | " + expected_message);
+      print("Source   | " + test.src);
+      print("         | " + test.err);
+
+      if (e === null) {
+        print("FAILED");
+        throw new Error("SyntaxError was not thrown");
+      }
+
+      var details = %GetExceptionDetails(e);
+      if (details.start_pos == undefined ||
+          details.end_pos == undefined) {
+        throw new Error("Bad message object returned");
+      }
+      var underline = " ".repeat(details.start_pos) +
+                      "^".repeat(details.end_pos - details.start_pos);
+      var passed = expected_message === e.toString() &&
+                   test.err === underline;
+
+      if (passed) {
+        print("PASSED");
+        print();
+      } else {
+        print("---------------------------------------");
+        print("Actual   | " + e);
+        print("Source   | " + test.src);
+        print("         | " + underline);
+        print("FAILED");
+        throw new Error("Test failed");
+      }
+    }
+  }
+})();
+
+
+(function() {
+  for (var src of NoErrorTests) {
+    print("=======================================");
+    print("Source   | " + src);
+    Realm.eval(0, src);
+    print("PASSED");
+    print();
+  }
+})();

test/mjsunit/es8/syntactic-tail-call-parsing.js

@@ -4,6 +4,7 @@
 
 // Flags: --allow-natives-syntax --harmony-explicit-tailcalls
 // Flags: --harmony-do-expressions
+"use strict";
 
 var SyntaxErrorTests = [
   { msg: "Unexpected expression inside tail call",
@@ -222,17 +223,14 @@ var SyntaxErrorTests = [
       { src: `()=>{ switch (continue foo()) { case 1: break; } ; }`,
         err: `              ^^^^^^^^^^^^^^`,
       },
-      { src: `()=>{ with (continue foo()) { smth; } }`,
-        err: `            ^^^^^^^^^^^^^^`,
-      },
       { src: `()=>{ let x = continue foo() }`,
         err: `              ^^^^^^^^^^^^^^`,
       },
       { src: `()=>{ const c = continue  foo() }`,
         err: `                ^^^^^^^^^^^^^^^`,
       },
-      { src: `class A {}; class B extends A { constructor() { return continue super () ; } }`,
-        err: `                                                       ^^^^^^^^^^^^^^^^^`,
+      { src: `class A {}; class B extends A { constructor() { return continue foo () ; } }`,
+        err: `                                                       ^^^^^^^^^^^^^^^`,
       },
       { src: `class A extends continue f () {}; }`,
         err: `                ^^^^^^^^^^^^^`,
@@ -312,13 +310,13 @@ var NoErrorTests = [
 
 
 (function() {
-  for (test_set of SyntaxErrorTests) {
+  for (var test_set of SyntaxErrorTests) {
     var expected_message = "SyntaxError: " + test_set.msg;
-    for (test of test_set.tests) {
+    for (var test of test_set.tests) {
       var passed = true;
       var e = null;
       try {
-        Realm.eval(0, test.src);
+        eval(test.src);
       } catch (ee) {
         e = ee;
       }
@@ -359,9 +357,10 @@ var NoErrorTests = [
 
 
 (function() {
-  for (src of NoErrorTests) {
+  for (var src of NoErrorTests) {
     print("=======================================");
     print("Source   | " + src);
+    src = `"use strict"; ` + src;
     Realm.eval(0, src);
     print("PASSED");
     print();

test/mjsunit/es8/syntactic-tail-call-simple.js

@@ -4,10 +4,27 @@
 
 // Flags: --allow-natives-syntax --harmony-explicit-tailcalls --stack-size=100
 
+//
+// Tail calls work only in strict mode.
+//
+(function() {
+  function f(n) {
+    if (n <= 0) {
+      return "foo";
+    }
+    return f(n - 1);
+  }
+  assertThrows(()=>{ f(1e5) });
+  %OptimizeFunctionOnNextCall(f);
+  assertThrows(()=>{ f(1e5) });
+})();
+
+
 //
 // Tail call normal functions.
 //
 (function() {
+  "use strict";
   function f(n) {
     if (n <= 0) {
       return "foo";
@@ -21,6 +38,7 @@
 
 
 (function() {
+  "use strict";
   function f(n) {
     if (n <= 0) {
       return  "foo";
@@ -34,6 +52,7 @@
 
 
 (function() {
+  "use strict";
   function f(n){
     if (n <= 0) {
       return "foo";
@@ -55,6 +74,7 @@
 
 
 (function() {
+  "use strict";
   function f(n){
     if (n <= 0) {
       return "foo";
@@ -79,6 +99,7 @@
 // Tail call bound functions.
 //
 (function() {
+  "use strict";
   function f0(n) {
     if (n <= 0) {
       return "foo";
@@ -96,6 +117,7 @@
 
 
 (function() {
+  "use strict";
   function f0(n){
     if (n <= 0) {
       return "foo";

test/mjsunit/es8/syntactic-tail-call.js

@@ -5,6 +5,8 @@
 // Flags: --allow-natives-syntax --harmony-explicit-tailcalls
 // Flags: --harmony-do-expressions
 
+"use strict";
+
 Error.prepareStackTrace = (error,stack) => {
   error.strace = stack;
   return error.message + "\n    at " + stack.join("\n    at ");
@@ -20,6 +22,8 @@ function CheckStackTrace(expected) {
     assertEquals(expected[i].name, stack[i + 1].getFunctionName());
   }
 }
+%NeverOptimizeFunction(CheckStackTrace);
+
 
 function f(expected_call_stack, a, b) {
   CheckStackTrace(expected_call_stack);
@@ -221,6 +225,87 @@ function f_153(expected_call_stack, a) {
 })();
 
 
+// Tail calling from getter.
+(function() {
+  function g(v) {
+    CheckStackTrace([g, test]);
+    %DeoptimizeFunction(test);
+    return 153;
+  }
+  %NeverOptimizeFunction(g);
+
+  function f(v) {
+    return continue g();
+  }
+  %SetForceInlineFlag(f);
+
+  function test() {
+    var o = {};
+    o.__defineGetter__('p', f);
+    assertEquals(153, o.p);
+  }
+
+  test();
+  test();
+  %OptimizeFunctionOnNextCall(test);
+  test();
+})();
+
+
+// Tail calling from setter.
+(function() {
+  function g() {
+    CheckStackTrace([g, test]);
+    %DeoptimizeFunction(test);
+    return 153;
+  }
+  %NeverOptimizeFunction(g);
+
+  function f(v) {
+    return continue g();
+  }
+  %SetForceInlineFlag(f);
+
+  function test() {
+    var o = {};
+    o.__defineSetter__('q', f);
+    assertEquals(1, o.q = 1);
+  }
+
+  test();
+  test();
+  %OptimizeFunctionOnNextCall(test);
+  test();
+})();
+
+
+// Tail calling from constructor.
+(function() {
+  function g(context) {
+    CheckStackTrace([g, test]);
+    %DeoptimizeFunction(test);
+    return {x: 153};
+  }
+  %NeverOptimizeFunction(g);
+
+  function A() {
+    this.x = 42;
+    return continue g();
+  }
+
+  function test() {
+    var o = new A();
+    %DebugPrint(o);
+    assertEquals(153, o.x);
+  }
+
+  test();
+  test();
+  %OptimizeFunctionOnNextCall(test);
+  test();
+})();
+
+
 // Tail calling via various expressions.
 (function() {
   function g1(a) {
@@ -294,6 +379,38 @@ function f_153(expected_call_stack, a) {
 })();
 
 
+// Tail calling from various statements.
+(function() {
+  function g3() {
+    for (var i = 0; i < 10; i++) {
+      return continue f_153([f_153, test]);
+    }
+  }
+
+  function g4() {
+    while (true) {
+      return continue f_153([f_153, test]);
+    }
+  }
+
+  function g5() {
+    do {
+      return continue f_153([f_153, test]);
+    } while (true);
+  }
+
+  function test() {
+    assertEquals(153, g3());
+    assertEquals(153, g4());
+    assertEquals(153, g5());
+  }
+  test();
+  test();
+  %OptimizeFunctionOnNextCall(test);
+  test();
+})();
+
+
 // Test tail calls from try-catch constructs.
 (function() {
   function tc1(a) {