[SemaObjC] Properly handle mix between type arguments and protocols.

Under certain conditions clang currently fails to properly diagnostic ObjectC
parameter list when type args and protocols are mixed in the same list. This
happens when the first item in the parameter list is a (1) protocol, (2)
unknown type or (3) a list of protocols/unknown types up to the first type
argument. Fix the problem to report the proper error, example:

NSArray<M, NSValue *, NSURL, NSArray <id <M>>> *foo = @[@"a"];
NSNumber *bar = foo[0];
NSLog(@"%@", bar);

$ clang ...
x.m:7:13: error: angle brackets contain both a type ('NSValue') and a protocol ('M')
        NSArray<M, NSValue *, NSURL, NSArray <id <M>>> *foo = @[@"a"];
                ~  ^

Differential Revision: http://reviews.llvm.org/D18997

rdar://problem/22204367

llvm-svn: 266245

clang/include/clang/Sema/Sema.h

@@ -7324,6 +7324,12 @@ public:
                                ArrayRef<IdentifierLocPair> ProtocolId,
                                SmallVectorImpl<Decl *> &Protocols);
 
+  void DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
+                                    SourceLocation ProtocolLoc,
+                                    IdentifierInfo *TypeArgId,
+                                    SourceLocation TypeArgLoc,
+                                    bool SelectProtocolFirst = false);
+
   /// Given a list of identifiers (and their locations), resolve the
   /// names to either Objective-C protocol qualifiers or type
   /// arguments, as appropriate.

clang/lib/Parse/ParseObjc.cpp

@@ -1693,11 +1693,18 @@ void Parser::parseObjCTypeArgsOrProtocolQualifiers(
     return;
   }
 
-  // We syntactically matched a type argument, so commit to parsing
-  // type arguments.
+  // We parsed an identifier list but stumbled into non single identifiers, this
+  // means we might (a) check that what we already parsed is a legitimate type
+  // (not a protocol or unknown type) and (b) parse the remaining ones, which
+  // must all be type args.
 
   // Convert the identifiers into type arguments.
   bool invalid = false;
+  IdentifierInfo *foundProtocolId = nullptr, *foundValidTypeId = nullptr;
+  SourceLocation foundProtocolSrcLoc, foundValidTypeSrcLoc;
+  SmallVector<IdentifierInfo *, 2> unknownTypeArgs;
+  SmallVector<SourceLocation, 2> unknownTypeArgsLoc;
+
   for (unsigned i = 0, n = identifiers.size(); i != n; ++i) {
     ParsedType typeArg
       = Actions.getTypeName(*identifiers[i], identifierLocs[i], getCurScope());
@@ -1711,17 +1718,32 @@ void Parser::parseObjCTypeArgsOrProtocolQualifiers(
       // Form a declarator to turn this into a type.
       Declarator D(DS, Declarator::TypeNameContext);
       TypeResult fullTypeArg = Actions.ActOnTypeName(getCurScope(), D);
-      if (fullTypeArg.isUsable())
+      if (fullTypeArg.isUsable()) {
         typeArgs.push_back(fullTypeArg.get());
-      else
+        if (!foundValidTypeId) {
+          foundValidTypeId = identifiers[i];
+          foundValidTypeSrcLoc = identifierLocs[i];
+        }
+      } else {
         invalid = true;
+        unknownTypeArgs.push_back(identifiers[i]);
+        unknownTypeArgsLoc.push_back(identifierLocs[i]);
+      }
     } else {
       invalid = true;
+      if (!Actions.LookupProtocol(identifiers[i], identifierLocs[i])) {
+        unknownTypeArgs.push_back(identifiers[i]);
+        unknownTypeArgsLoc.push_back(identifierLocs[i]);
+      } else if (!foundProtocolId) {
+        foundProtocolId = identifiers[i];
+        foundProtocolSrcLoc = identifierLocs[i];
+      }
     }
   }
 
   // Continue parsing type-names.
   do {
+    Token CurTypeTok = Tok;
     TypeResult typeArg = ParseTypeName();
 
     // Consume the '...' for a pack expansion.
@@ -1733,11 +1755,28 @@ void Parser::parseObjCTypeArgsOrProtocolQualifiers(
 
     if (typeArg.isUsable()) {
       typeArgs.push_back(typeArg.get());
+      if (!foundValidTypeId) {
+        foundValidTypeId = CurTypeTok.getIdentifierInfo();
+        foundValidTypeSrcLoc = CurTypeTok.getLocation();
+      }
     } else {
       invalid = true;
     }
   } while (TryConsumeToken(tok::comma));
 
+  // Diagnose the mix between type args and protocols.
+  if (foundProtocolId && foundValidTypeId)
+    Actions.DiagnoseTypeArgsAndProtocols(foundProtocolId, foundProtocolSrcLoc,
+                                         foundValidTypeId,
+                                         foundValidTypeSrcLoc);
+
+  // Diagnose unknown arg types.
+  ParsedType T;
+  if (unknownTypeArgs.size())
+    for (unsigned i = 0, e = unknownTypeArgsLoc.size(); i < e; ++i)
+      Actions.DiagnoseUnknownTypeName(unknownTypeArgs[i], unknownTypeArgsLoc[i],
+                                      getCurScope(), nullptr, T);
+
   // Parse the closing '>'.
   SourceLocation rAngleLoc;
   (void)ParseGreaterThanInTemplateList(rAngleLoc, consumeLastToken,

clang/lib/Sema/SemaDeclObjC.cpp

@@ -1303,6 +1303,16 @@ class ObjCTypeArgOrProtocolValidatorCCC : public CorrectionCandidateCallback {
 };
 } // end anonymous namespace
 
+void Sema::DiagnoseTypeArgsAndProtocols(IdentifierInfo *ProtocolId,
+                                        SourceLocation ProtocolLoc,
+                                        IdentifierInfo *TypeArgId,
+                                        SourceLocation TypeArgLoc,
+                                        bool SelectProtocolFirst) {
+  Diag(TypeArgLoc, diag::err_objc_type_args_and_protocols)
+      << SelectProtocolFirst << TypeArgId << ProtocolId
+      << SourceRange(ProtocolLoc);
+}
+
 void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
        Scope *S,
        ParsedType baseType,
@@ -1570,11 +1580,9 @@ void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
 
       // We have a conflict: some names refer to protocols and others
       // refer to types.
-      Diag(identifierLocs[i], diag::err_objc_type_args_and_protocols)
-        << (protocols[i] != nullptr)
-        << identifiers[i]
-        << identifiers[0]
-        << SourceRange(identifierLocs[0]);
+      DiagnoseTypeArgsAndProtocols(identifiers[0], identifierLocs[0],
+                                   identifiers[i], identifierLocs[i],
+                                   protocols[i] != nullptr);
 
       protocols.clear();
       typeArgs.clear();

clang/test/SemaObjC/parameterized_classes.m

@@ -240,6 +240,10 @@ typedef PC4<NSObject, NSObject, ObjCStringref> typeArgs5; // expected-error{{unk
 
 // Type/protocol conflict.
 typedef PC4<NSCopying, ObjCStringRef> typeArgsProtocolQualsConflict1; // expected-error{{angle brackets contain both a type ('ObjCStringRef') and a protocol ('NSCopying')}}
+typedef PC4<NSCopying, NSString *> typeArgsProtocolQualsConflict2; // expected-error{{angle brackets contain both a type ('NSString') and a protocol ('NSCopying')}}
+typedef PC4<NSCopying, UnknownType, NSString *> typeArgsProtocolQualsConflict3; // expected-error{{angle brackets contain both a type ('NSString') and a protocol ('NSCopying')}} expected-error{{unknown type name 'UnknownType'}}
+typedef PC4<UnknownType, NSString *> typeArgsProtocolQualsConflict4; // expected-error{{unknown type name 'UnknownType'}}
+typedef PC4<NSString, NSCopying, NSString *> typeArgsProtocolQualsConflict5; // expected-error{{angle brackets contain both a type ('NSString') and a protocol ('NSCopying')}}
 
 // Handling the '>>' in type argument lists.
 typedef PC4<id<NSCopying>, NSObject *, id<NSObject>> typeArgs6;