Adjust Dart.g to allow constructor tearoffs

This CL updates the grammar Dart.g such that it
supports constructor tearoffs, as well as explicit
instantiations of generic functions and methods,
and parameterized types as type literals.

Change-Id: I2e30d0eb185b84fc2103c21ba962f4cbff40905a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/197161
Reviewed-by: Lasse R.H. Nielsen <[email protected]>
Commit-Queue: Erik Ernst <[email protected]>

Author: eernstg

tools/spec_parser/Dart.g

@@ -420,11 +420,11 @@ constructorSignature
     ;
 
 constructorName
-    :    typeIdentifier ('.' identifier)?
+    :    typeIdentifier ('.' (identifier | NEW))?
     ;
 
 redirection
-    :    ':' THIS ('.' identifier)? arguments
+    :    ':' THIS ('.' (identifier | NEW))? arguments
     ;
 
 initializers
@@ -433,7 +433,7 @@ initializers
 
 initializerListEntry
     :    SUPER arguments
-    |    SUPER '.' identifier arguments
+    |    SUPER '.' (identifier | NEW) arguments
     |    fieldInitializer
     |    assertion
     ;
@@ -519,10 +519,12 @@ primary
     |    '(' expression ')'
     |    literal
     |    identifier
+    |    constructorTearoff
     ;
 
 constructorInvocation
-    :    typeName typeArguments '.' identifier arguments
+    :    typeName typeArguments '.' NEW arguments
+    |    typeName '.' NEW arguments
     ;
 
 literal
@@ -598,6 +600,10 @@ forElement
     : AWAIT? FOR '(' forLoopParts ')' element
     ;
 
+constructorTearoff
+    :    typeName typeArguments? '.' NEW
+    ;
+
 throwExpression
     :    THROW expression
     ;
@@ -850,6 +856,7 @@ selector
     :    '!'
     |    assignableSelector
     |    argumentPart
+    |    typeArguments
     ;
 
 argumentPart
@@ -900,8 +907,8 @@ identifier
     ;
 
 qualifiedName
-    :    typeIdentifier '.' identifier
-    |    typeIdentifier '.' typeIdentifier '.' identifier
+    :    typeIdentifier '.' (identifier | NEW)
+    |    typeIdentifier '.' typeIdentifier '.' (identifier | NEW)
     ;
 
 typeIdentifier
@@ -1249,7 +1256,7 @@ typedIdentifier
 constructorDesignation
     :    typeIdentifier
     |    qualifiedName
-    |    typeName typeArguments ('.' identifier)?
+    |    typeName typeArguments ('.' (identifier | NEW))?
     ;
 
 symbolLiteral