Drop the Identifier List from Designated Type Parsing

This was never the correct way to model this because it drops
the commas in the list. Instead just take the optional trailing
identifier element if we have one.

Author: CodaFi

lib/Parse/ParseDecl.cpp

@@ -8863,12 +8863,13 @@ Parser::parseDeclOperatorImpl(SourceLoc OperatorLoc, Identifier Name,
       return makeParserCodeCompletionResult<OperatorDecl>();
     }
 
-    SyntaxParsingContext ListCtxt(SyntaxContext, SyntaxKind::IdentifierList);
-
     (void)parseIdentifier(groupName, groupLoc,
                           diag::operator_decl_expected_precedencegroup,
                           /*diagnoseDollarPrefix=*/false);
 
+    SyntaxParsingContext ListCtxt(SyntaxContext,
+                                  SyntaxKind::DesignatedTypeList);
+
     if (Context.TypeCheckerOpts.EnableOperatorDesignatedTypes) {
       // Designated types have been removed; consume the list (mainly for source
       // compatibility with old swiftinterfaces) and emit a warning.
@@ -8885,9 +8886,17 @@ Parser::parseDeclOperatorImpl(SourceLoc OperatorLoc, Identifier Name,
         typesEndLoc = groupLoc;
       }
 
-      while (consumeIf(tok::comma, typesEndLoc)) {
-        if (Tok.isNot(tok::eof))
+      while (Tok.isNot(tok::eof)) {
+        SyntaxParsingContext ElementCtxt(SyntaxContext,
+                                         SyntaxKind::DesignatedTypeElement);
+        if (!consumeIf(tok::comma, typesEndLoc)) {
+          ElementCtxt.setTransparent();
+          break;
+        }
+
+        if (Tok.isNot(tok::eof)) {
           typesEndLoc = consumeToken();
+        }
       }
 
       if (typesEndLoc.isValid())

test/Parse/operator_decl_designated_types.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -enable-operator-designated-types -verify-syntax-tree
+// RUN: %target-typecheck-verify-swift -enable-operator-designated-types
 
 precedencegroup LowPrecedence {
   associativity: right