2 files changed, 71 insertions, 3 deletions
diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 3dbecd09008..0f90b684685 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -319,7 +319,8 @@ Decl *Parser::ParseObjCAtInterfaceDeclaration(SourceLocation AtLoc,
 
     // Type arguments for the superclass or protocol conformances.
     if (Tok.is(tok::less)) {
-      parseObjCTypeArgsOrProtocolQualifiers(typeArgsLAngleLoc,
+      parseObjCTypeArgsOrProtocolQualifiers(ParsedType(),
+                                            typeArgsLAngleLoc,
                                             typeArgs,
                                             typeArgsRAngleLoc,
                                             LAngleLoc,
@@ -1589,6 +1590,7 @@ TypeResult Parser::parseObjCProtocolQualifierType(SourceLocation &rAngleLoc) {
 ///     '<' type-name '...'[opt] (',' type-name '...'[opt])* '>'
 ///
 void Parser::parseObjCTypeArgsOrProtocolQualifiers(
+       ParsedType baseType,
        SourceLocation &typeArgsLAngleLoc,
        SmallVectorImpl<ParsedType> &typeArgs,
        SourceLocation &typeArgsRAngleLoc,
@@ -1648,6 +1650,7 @@ void Parser::parseObjCTypeArgsOrProtocolQualifiers(
 
     // Let Sema figure out what we parsed.
     Actions.actOnObjCTypeArgsOrProtocolQualifiers(getCurScope(),
+                                                  baseType,
                                                   lAngleLoc,
                                                   identifiers,
                                                   identifierLocs,
@@ -1723,6 +1726,7 @@ void Parser::parseObjCTypeArgsOrProtocolQualifiers(
 }
 
 void Parser::parseObjCTypeArgsAndProtocolQualifiers(
+       ParsedType baseType,
        SourceLocation &typeArgsLAngleLoc,
        SmallVectorImpl<ParsedType> &typeArgs,
        SourceLocation &typeArgsRAngleLoc,
@@ -1734,7 +1738,8 @@ void Parser::parseObjCTypeArgsAndProtocolQualifiers(
   assert(Tok.is(tok::less));
 
   // Parse the first angle-bracket-delimited clause.
-  parseObjCTypeArgsOrProtocolQualifiers(typeArgsLAngleLoc,
+  parseObjCTypeArgsOrProtocolQualifiers(baseType,
+                                        typeArgsLAngleLoc,
                                         typeArgs,
                                         typeArgsRAngleLoc,
                                         protocolLAngleLoc,
@@ -1786,7 +1791,7 @@ TypeResult Parser::parseObjCTypeArgsAndProtocolQualifiers(
   SourceLocation protocolRAngleLoc;
 
   // Parse type arguments and protocol qualifiers.
-  parseObjCTypeArgsAndProtocolQualifiers(typeArgsLAngleLoc, typeArgs,
+  parseObjCTypeArgsAndProtocolQualifiers(type, typeArgsLAngleLoc, typeArgs,
                                          typeArgsRAngleLoc, protocolLAngleLoc,
                                          protocols, protocolLocs,
                                          protocolRAngleLoc, consumeLastToken);
diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 48aa2467d24..74fbec23545 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -1220,6 +1220,7 @@ class ObjCTypeArgOrProtocolValidatorCCC : public CorrectionCandidateCallback {
 
 void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
        Scope *S,
+       ParsedType baseType,
        SourceLocation lAngleLoc,
        ArrayRef<IdentifierInfo *> identifiers,
        ArrayRef<SourceLocation> identifierLocs,
@@ -1237,6 +1238,27 @@ void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
   auto resolvedAsProtocols = [&] {
     assert(numProtocolsResolved == identifiers.size() && "Unresolved protocols");
     
+    // Determine whether the base type is a parameterized class, in
+    // which case we want to warn about typos such as
+    // "NSArray<NSObject>" (that should be NSArray<NSObject *>).
+    ObjCInterfaceDecl *baseClass = nullptr;
+    QualType base = GetTypeFromParser(baseType, nullptr);
+    bool allAreTypeNames = false;
+    SourceLocation firstClassNameLoc;
+    if (!base.isNull()) {
+      if (const auto *objcObjectType = base->getAs<ObjCObjectType>()) {
+        baseClass = objcObjectType->getInterface();
+        if (baseClass) {
+          if (auto typeParams = baseClass->getTypeParamList()) {
+            if (typeParams->size() == numProtocolsResolved) {
+              // Note that we should be looking for type names, too.
+              allAreTypeNames = true;
+            }
+          }
+        }
+      }
+    }
+
     for (unsigned i = 0, n = protocols.size(); i != n; ++i) {
       ObjCProtocolDecl *&proto 
         = reinterpret_cast<ObjCProtocolDecl *&>(protocols[i]);
@@ -1261,6 +1283,47 @@ void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
         Diag(forwardDecl->getLocation(), diag::note_protocol_decl_undefined)
           << forwardDecl;
       }
+
+      // If everything this far has been a type name (and we care
+      // about such things), check whether this name refers to a type
+      // as well.
+      if (allAreTypeNames) {
+        if (auto *decl = LookupSingleName(S, identifiers[i], identifierLocs[i],
+                                          LookupOrdinaryName)) {
+          if (isa<ObjCInterfaceDecl>(decl)) {
+            if (firstClassNameLoc.isInvalid())
+              firstClassNameLoc = identifierLocs[i];
+          } else if (!isa<TypeDecl>(decl)) {
+            // Not a type.
+            allAreTypeNames = false;
+          }
+        } else {
+          allAreTypeNames = false;
+        }
+      }
+    }
+    
+    // All of the protocols listed also have type names, and at least
+    // one is an Objective-C class name. Check whether all of the
+    // protocol conformances are declared by the base class itself, in
+    // which case we warn.
+    if (allAreTypeNames && firstClassNameLoc.isValid()) {
+      llvm::SmallPtrSet<ObjCProtocolDecl*, 8> knownProtocols;
+      Context.CollectInheritedProtocols(baseClass, knownProtocols);
+      bool allProtocolsDeclared = true;
+      for (auto proto : protocols) {
+        if (knownProtocols.count(static_cast<ObjCProtocolDecl *>(proto)) == 0) {
+          allProtocolsDeclared = false;
+          break;
+        }
+      }
+
+      if (allProtocolsDeclared) {
+        Diag(firstClassNameLoc, diag::warn_objc_redundant_qualified_class_type)
+          << baseClass->getDeclName() << SourceRange(lAngleLoc, rAngleLoc)
+          << FixItHint::CreateInsertion(
+               PP.getLocForEndOfToken(firstClassNameLoc), " *");
+      }
     }
 
     protocolLAngleLoc = lAngleLoc;