Update Dart.g to match the current pattern feature spec

This CL changes the Dart grammar in Dart.g such that it contains all
the grammar changes applied to the patterns proposal since the previous
update of Dart.g.

Change-Id: I9b5f0d9a092d30ce0055db99da5fdbe3b9b1d5dc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/275002
Reviewed-by: William Hesse <whesse@google.com>
Auto-Submit: Erik Ernst <eernst@google.com>
Commit-Queue: Erik Ernst <eernst@google.com>

tools/spec_parser/Dart.g

@@ -4,9 +4,12 @@
 
 // CHANGES:
 //
-// v0.24 Change constant pattern rules to allow Symbols and negative numbers
+// v0.25 Update pattern rules following changes to the patterns feature
+// specification since v0.24.
 //
-// v0.23 Change logical pattern rules to || and &&
+// v0.24 Change constant pattern rules to allow Symbols and negative numbers.
+//
+// v0.23 Change logical pattern rules to || and &&.
 //
 // v0.22 Change pattern rules, following updated feature specification.
 //
@@ -656,7 +659,7 @@ spreadElement
     ;
 
 ifElement
-    : IF '(' expression ')' element (ELSE element)?
+    : ifCondition element (ELSE element)?
     ;
 
 forElement
@@ -669,15 +672,11 @@ constructorTearoff
 
 switchExpression
     :    SWITCH '(' expression ')'
-         LBRACE switchExpressionCase* switchExpressionDefault? RBRACE
+         LBRACE switchExpressionCase (',' switchExpressionCase)* ','? RBRACE
     ;
 
 switchExpressionCase
-    :    caseHead '=>' expression ';'
+    :    guardedPattern '=>' expression
-    ;
-
-switchExpressionDefault
-    : DEFAULT '=>' expression ';'
     ;
 
 throwExpression
@@ -1031,7 +1030,7 @@ logicalAndPattern
     ;
 
 relationalPattern
-    :    (equalityOperator | relationalOperator) relationalExpression
+    :    (equalityOperator | relationalOperator) bitwiseOrExpression
     |    unaryPattern
     ;
 
@@ -1087,7 +1086,20 @@ parenthesizedPattern
     ;
 
 listPattern
-    :    typeArguments? '[' patterns? ']'
+    :    typeArguments? '[' listPatternElements? ']'
+    ;
+
+listPatternElements
+    :    listPatternElement (',' listPatternElement)* ','?
+    ;
+
+listPatternElement
+    :    pattern
+    |    restPattern
+    ;
+
+restPattern
+    :    '...' pattern?
     ;
 
 mapPattern
@@ -1100,6 +1112,7 @@ mapPatternEntries
 
 mapPatternEntry
     :    expression ':' pattern
+    |    '...'
     ;
 
 recordPattern
@@ -1186,7 +1199,11 @@ localFunctionDeclaration
     ;
 
 ifStatement
-    :    IF '(' expression caseHead? ')' statement (ELSE statement)?
+    :    ifCondition statement (ELSE statement)?
+    ;
+
+ifCondition
+    :    IF '(' expression (CASE guardedPattern)? ')'
     ;
 
 forStatement
@@ -1222,11 +1239,11 @@ switchStatement
     ;
 
 switchStatementCase
-    :    label* caseHead ':' statements
+    :    label* CASE guardedPattern ':' statements
     ;
 
-caseHead
+guardedPattern
-    :    CASE pattern (WHEN expression)?
+    :    pattern (WHEN expression)?
     ;
 
 switchStatementDefault
@@ -1393,7 +1410,7 @@ recordType
     :    '(' ')'
     |    '(' recordTypeFields ',' recordTypeNamedFields ')'
     |    '(' recordTypeFields ','? ')'
-    |    '(' recordTypeNamedFields? ')'
+    |    '(' recordTypeNamedFields ')'
     ;
 
 recordTypeFields