Also check for error_type in ObjC keypath validation.

And add a test that exercises this exit path (although it won't crash
a compiler without my fixes because we do end up with ErrorType in
that case, not a nullptr).

Author: rudkx

lib/Sema/TypeCheckExprObjC.cpp

@@ -317,8 +317,10 @@ Optional<Type> TypeChecker::checkObjCKeyPathExpr(DeclContext *dc,
     // Handle property references.
     if (auto var = dyn_cast<VarDecl>(found)) {
       validateDecl(var);
-      if (var->isInvalid() || !var->hasInterfaceType())
+      if (var->isInvalid() || !var->hasInterfaceType() ||
+          var->getInterfaceType()->hasError()) {
         return None;
+      }
 
       // Resolve this component to the variable we found.
       auto varRef = ConcreteDeclRef(var);

test/expr/primary/keypath/keypath-objc.swift

@@ -4,7 +4,7 @@ import Foundation
 
 // REQUIRES: objc_interop
 
-@objc class A : NSObject {
+@objc class A : NSObject { // expected-error {{class 'A' has no initializers}}
   @objc var propB: B = B()
   @objc var propString: String = "" // expected-note {{did you mean 'propString'}}
   @objc var propArray: [String] = []
@@ -21,6 +21,8 @@ import Foundation
   @objc func someMethod() { }
 
   @objc var `repeat`: String?
+
+  @objc var noType // expected-error {{type annotation missing in pattern}}
 }
 
 @objc class B : NSObject  {
@@ -106,6 +108,9 @@ func testKeyPath(a: A, b: B) {
   // Property with keyword name.
   let _: String = #keyPath(A.repeat)
 
+  // Property with no type
+  let _: String = #keyPath(A.noType)
+
   // Nested type of a bridged type (rdar://problem/28061409).
   typealias IntArray = [Int]
   let _: String = #keyPath(IntArray.Foo.propString)