Add support for static access shorthands

Change-Id: I826e230ad38388a8e1f6ccc366704a2e8c340dee
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397301
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Erik Ernst <[email protected]>

Author: eernstg

tools/spec_parser/Dart.g

@@ -4,6 +4,8 @@
 
 // CHANGES:
 //
+// v0.52 Support static access shorthands.
+//
 // v0.51 Support a `switchExpression` with no cases.
 //
 // v0.50 Add support for digit separators in numeric literals.
@@ -681,6 +683,7 @@ primary
     |    '(' expression ')'
     |    constructorTearoff
     |    switchExpression
+    |    staticMemberShorthand
     ;
 
 constructorInvocation
@@ -796,6 +799,11 @@ switchExpressionCase
     :    guardedPattern '=>' expression
     ;
 
+staticMemberShorthand
+    :    '.' identifierOrNew selector*
+    |    CONST '.' identifierOrNew selector*
+    ;
+
 throwExpression
     :    THROW expression
     ;
@@ -1170,6 +1178,7 @@ constantPattern
     |    CONST typeArguments? '[' elements? ']'
     |    CONST typeArguments? LBRACE elements? RBRACE
     |    CONST '(' expression ')'
+    |    staticMemberShorthand
     ;
 
 variablePattern

tools/spec_parser/dart_spec_parser/Dart.g4

@@ -4,6 +4,8 @@
 
 // CHANGES:
 //
+// v0.53 Support static access shorthands.
+//
 // v0.52 Support a `switchExpression` with no cases.
 //
 // v0.51 Add support for digit separators in numeric literals.
@@ -687,6 +689,7 @@ primary
     |    '(' expression ')'
     |    constructorTearoff
     |    switchExpression
+    |    staticMemberShorthand
     ;
 
 constructorInvocation
@@ -802,6 +805,11 @@ switchExpressionCase
     :    guardedPattern '=>' expression
     ;
 
+staticMemberShorthand
+    :    '.' identifierOrNew selector*
+    |    CONST '.' identifierOrNew selector*
+    ;
+
 throwExpression
     :    THROW expression
     ;
@@ -1176,6 +1184,7 @@ constantPattern
     |    CONST typeArguments? '[' elements? ']'
     |    CONST typeArguments? LBRACE elements? RBRACE
     |    CONST '(' expression ')'
+    |    staticMemberShorthand
     ;
 
 variablePattern