Accept a trailing comma in asserts in initializer lists (issue 31320)

Change-Id: I6166aac91abc65c0817d14e1d98f5944236016bf
Reviewed-on: https://dart-review.googlesource.com/29520
Commit-Queue: Brian Wilkerson <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: bwilkerson

pkg/analyzer/lib/src/generated/parser.dart

@@ -6455,7 +6455,14 @@ class Parser {
     Expression message;
     if (_matches(TokenType.COMMA)) {
       comma = getAndAdvance();
-      message = parseExpression2();
+      if (_matches(TokenType.CLOSE_PAREN)) {
+        comma = null;
+      } else {
+        message = parseExpression2();
+        if (_matches(TokenType.COMMA)) {
+          getAndAdvance();
+        }
+      }
     }
     Token rightParen = _expect(TokenType.CLOSE_PAREN);
     return astFactory.assertInitializer(

tests/language/language_analyzer2.status

@@ -397,11 +397,8 @@ void_type_test: StaticWarning
 *: Skip # Issue 28649
 
 [ $compiler == dart2analyzer && $runtime == none ]
-assertion_initializer_const_error2_test/cc10: CompileTimeError # Issue #31320
-assertion_initializer_const_error2_test/cc11: CompileTimeError # Issue #31320
 assertion_initializer_const_function_error_test/01: MissingCompileTimeError
 assertion_initializer_const_function_test/01: MissingStaticWarning
-assertion_initializer_test: CompileTimeError
 
 [ $compiler == dart2analyzer && $runtime == none && $checked ]
 assertion_initializer_const_error2_test/*: MissingCompileTimeError # Issue #

tests/language_2/language_2_analyzer.status

@@ -154,8 +154,6 @@ vm/reflect_core_vm_test: CompileTimeError
 vm/regress_27201_test: SkipByDesign # Loads bad library, so will always crash.
 
 [ $compiler == dart2analyzer && $runtime == none ]
-assertion_initializer_const_error2_test/cc10: CompileTimeError # Issue 31320
-assertion_initializer_const_error2_test/cc11: CompileTimeError # Issue 31320
 assertion_initializer_const_function_test/01: CompileTimeError
 assertion_initializer_test: CompileTimeError
 error_stacktrace_test/00: MissingCompileTimeError
@@ -1205,8 +1203,6 @@ additional_interface_adds_optional_args_supercall_test: MissingCompileTimeError
 additional_interface_adds_optional_args_test: StaticWarning
 argument_assignability_function_typed_test/01: MissingCompileTimeError
 argument_assignability_function_typed_test/02: MissingCompileTimeError
-assertion_initializer_const_error2_test/cc10: CompileTimeError # Issue 31320
-assertion_initializer_const_error2_test/cc11: CompileTimeError # Issue 31320
 assertion_initializer_const_function_test/01: MissingStaticWarning
 async_congruence_local_test/01: MissingCompileTimeError
 async_congruence_local_test/02: MissingCompileTimeError