[Parse] InitAccessors: Parse limited representation of init accessor in SIL context

Author: xedin

lib/Parse/ParseDecl.cpp

@@ -7281,7 +7281,7 @@ static void diagnoseRedundantAccessors(Parser &P, SourceLoc loc,
              /*already*/ true);
 }
 
-static bool isAllowedInProtocolRequirement(AccessorKind kind) {
+static bool isAllowedInProtocolRequirement(AccessorKind kind, bool forSIL) {
   switch (kind) {
   case AccessorKind::Get:
   case AccessorKind::Set:
@@ -7293,8 +7293,10 @@ static bool isAllowedInProtocolRequirement(AccessorKind kind) {
   case AccessorKind::DidSet:
   case AccessorKind::Read:
   case AccessorKind::Modify:
-  case AccessorKind::Init:
     return false;
+
+  case AccessorKind::Init:
+    return forSIL;
   }
   llvm_unreachable("bad accessor kind");
 }
@@ -7688,7 +7690,8 @@ ParserStatus Parser::parseGetSet(ParseDeclOptions Flags, ParameterList *Indices,
 
     // For now, immediately reject illegal accessors in protocols just to
     // avoid having to deal with them everywhere.
-    if (parsingLimitedSyntax && !isAllowedInProtocolRequirement(Kind)) {
+    if (parsingLimitedSyntax &&
+        !isAllowedInProtocolRequirement(Kind, SF.Kind == SourceFileKind::SIL)) {
       diagnose(Loc, diag::expected_getset_in_protocol);
       continue;
     }