[es8] More spec compliant syntactic tail calls implementation.

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index b4e7528974d760742ad03ef505a8ecda618bc74b..e018e04bfde9d7ecd43a0c1c044db98502ea5606 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -117,8 +117,7 @@ class CallSite {
   T(DebuggerType, "Debugger: Parameters have wrong types.")                    \
   T(DeclarationMissingInitializer, "Missing initializer in % declaration")     \
   T(DefineDisallowed, "Cannot define property:%, object is not extensible.")   \
-  T(DetachedOperation,                                                         \
-    "Cannot perform % on a detached ArrayBuffer")                              \
+  T(DetachedOperation, "Cannot perform % on a detached ArrayBuffer")           \
   T(DuplicateTemplateProperty, "Object template has duplicate property '%'")   \
   T(ExtendsValueGenerator,                                                     \
     "Class extends value % may not be a generator function")                   \
@@ -427,10 +426,6 @@ class CallSite {
     "inside a block.")                                                         \
   T(StrictOctalLiteral, "Octal literals are not allowed in strict mode.")      \
   T(StrictWith, "Strict mode code may not include a with statement")           \
-  T(TailCallInCatchBlock,                                                      \
-    "Tail call expression in catch block when finally block is also present.") \
-  T(TailCallInForInOf, "Tail call expression in for-in/of body.")              \
-  T(TailCallInTryBlock, "Tail call expression in try block.")                  \
   T(TemplateOctalLiteral,                                                      \
     "Octal literals are not allowed in template strings.")                     \
   T(ThisFormalParameter, "'this' is not a valid formal parameter name")        \
@@ -444,10 +439,16 @@ class CallSite {
   T(UnexpectedEOS, "Unexpected end of input")                                  \
   T(UnexpectedFunctionSent,                                                    \
     "function.sent expression is not allowed outside a generator")             \
+  T(UnexpectedInsideTailCall, "Unexpected expression inside tail call")        \
   T(UnexpectedReserved, "Unexpected reserved word")                            \
   T(UnexpectedStrictReserved, "Unexpected strict mode reserved word")          \
   T(UnexpectedSuper, "'super' keyword unexpected here")                        \
   T(UnexpectedNewTarget, "new.target expression is not allowed here")          \
+  T(UnexpectedTailCall, "Tail call expression is not allowed here")            \
+  T(UnexpectedTailCallInCatchBlock,                                            \
+    "Tail call expression in catch block when finally block is also present")  \
+  T(UnexpectedTailCallInForInOf, "Tail call expression in for-in/of body")     \
+  T(UnexpectedTailCallInTryBlock, "Tail call expression in try block")         \
   T(UnexpectedTemplateString, "Unexpected template string")                    \
   T(UnexpectedToken, "Unexpected token %")                                     \
   T(UnexpectedTokenIdentifier, "Unexpected identifier")                        \