Index: lib/Parse/ParseObjc.cpp
===================================================================
--- lib/Parse/ParseObjc.cpp
+++ lib/Parse/ParseObjc.cpp
@@ -1740,6 +1740,10 @@
     }
   }
 
+  // ParseTypeName() can advance the token stream up to tok::eof when there's
+  // an umatched token (e.g. "["). Restore the state in case this happens.
+  TentativeParsingAction TPA(*this);
+
   // Continue parsing type-names.
   do {
     Token CurTypeTok = Tok;
@@ -1763,6 +1767,11 @@
     }
   } while (TryConsumeToken(tok::comma));
 
+  if (Tok.is(tok::eof))
+    TPA.Revert();
+  else
+    TPA.Commit();
+
   // Diagnose the mix between type args and protocols.
   if (foundProtocolId && foundValidTypeId)
     Actions.DiagnoseTypeArgsAndProtocols(foundProtocolId, foundProtocolSrcLoc,
Index: test/SemaObjC/crash-on-type-args-protocols.m
===================================================================
--- /dev/null
+++ test/SemaObjC/crash-on-type-args-protocols.m
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -DFIRST -fsyntax-only -verify %s
+// RUN: %clang_cc1 -DSECOND -fsyntax-only -verify %s
+// RUN: %clang_cc1 -DTHIRD -fsyntax-only -verify %s
+
+@protocol P;
+@interface NSObject
+@end
+@protocol X
+@end
+@interface X : NSObject <X>
+@end
+
+@class A;
+
+#ifdef FIRST
+id<X> F1(id<[P> v) { // expected-error {{expected a type}} // expected-error {{use of undeclared identifier 'P'}} // expected-error {{use of undeclared identifier 'v'}} // expected-error {{expected '>'}} // expected-error {{expected ')'}} // expected-note {{to match this '('}}
+  return 0;
+}
+
+id<X> F2(id<P[X> v) { // expected-error {{unknown type name 'P'}} // expected-error {{unexpected interface name 'X': expected expression}} // expected-error {{use of undeclared identifier 'v'}} // expected-error {{expected '>'}} // expected-error {{unexpected interface name 'X': expected expression}} // expected-error {{use of undeclared identifier 'v'}} // expected-note {{to match this '('}}
+  return 0;
+}
+#endif
+
+#ifdef SECOND
+id<X> F3(id<P, P *[> v) { // expected-error {{unknown type name 'P'}} // expected-error {{expected expression}} // expected-error {{use of undeclared identifier 'v'}} // expected-error {{expected '>'}} // expected-error {{expected expression}} // expected-error {{use of undeclared identifier 'v'}} // expected-note {{to match this '('}}
+  return 0;
+}
+#endif
+
+#ifdef THIRD
+id<X> F4(id<P, P *(> v { // expected-error {{unknown type name 'P'}} // expected-error {{expected ')'}} // expected-error {{expected '>'}} // expected-error {{expected ')'}} // expected-note {{to match this '('}} // expected-note {{to match this '('}} // expected-note {{to match this '('}}
+  return 0;
+}
+#endif
+
+ // expected-error {{expected ')'}} // expected-error {{expected function body after function declarator}}