JET-177 Drop extensions

grammar/src/class_members.grm

@@ -41,7 +41,6 @@ memberDeclaration
   : function
   : property
   : class
-  : extension
   : typedef
   : anonymousInitializer
   ;

grammar/src/expressions.grm

@@ -149,7 +149,6 @@ isRHS
 declaration
   : function
   : property
-  : extension
   : class
   : typedef
   : object
@@ -259,7 +258,7 @@ arrayAccess
   ;
 
 objectLiteral
-  : "object" ":" delegationSpecifier{","}? classBody // Cannot make class body optional: foo(object F, a)
+  : "object" ":" delegationSpecifier{","}? classBody // Cannot make class body optional: foo(object : F, A)
   ;
 
 /* Factory methods:

grammar/src/toplevel.grm

@@ -38,7 +38,6 @@ toplevelObject
   : function
   : property
   : typedef
-  : extension
   ;
 
 namespace
@@ -55,9 +54,4 @@ bq. See [Namespaces]
 [undocumented]
 typedef
   : modifiers "type" SimpleName typeParameters? "=" type
-  ;
-
-[undocumented]
-extension
-  : modifiers "extension" SimpleName? typeParameters? "for" type classBody? // properties cannot be lazy, cannot have backing fields
-  ;
+  ;