Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -696,6 +696,7 @@
 // in -Wparentheses because most users who use -Wparentheses explicitly
 // do not want these warnings.
 def ParenthesesOnEquality : DiagGroup<"parentheses-equality">;
+def AssigmentInBoolContext : DiagGroup<"assigment-in-bool-context">;
 def Parentheses : DiagGroup<"parentheses",
                             [LogicalOpParentheses,
                              LogicalNotParentheses,
@@ -703,7 +704,8 @@
                              ShiftOpParentheses,
                              OverloadedShiftOpParentheses,
                              ParenthesesOnEquality,
-                             DanglingElse]>;
+                             DanglingElse,
+                             AssigmentInBoolContext]>;
 
 // -Wconversion has its own warnings, but we split a few out for
 // legacy reasons:
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -6733,9 +6733,9 @@
 def err_incomplete_object_call : Error<
   "incomplete type in call to object of type %0">;
 
-def warn_condition_is_assignment : Warning<"using the result of an "
-  "assignment as a condition without parentheses">,
-  InGroup<Parentheses>;
+def warn_condition_is_assignment : Warning<"converting the result of an "
+  "assignment to bool">,
+  InGroup<AssigmentInBoolContext>;
 // Completely identical except off by default.
 def warn_condition_is_idiomatic_assignment : Warning<"using the result "
   "of an assignment as a condition without parentheses">,
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4136,6 +4136,7 @@
   }
 
   case ICK_Boolean_Conversion:
+    DiagnoseAssignmentAsCondition(From->IgnoreImpCasts());
     // Perform half-to-boolean conversion via float.
     if (From->getType()->isHalfType()) {
       From = ImpCastExprToType(From, Context.FloatTy, CK_FloatingCast).get();
Index: test/CodeCompletion/crash-skipped-bodies-template-inst.cpp
===================================================================
--- test/CodeCompletion/crash-skipped-bodies-template-inst.cpp
+++ test/CodeCompletion/crash-skipped-bodies-template-inst.cpp
@@ -6,7 +6,7 @@
       int x;
       if (x = 10) {}
       // Check that body of this function is actually skipped.
-      // CHECK-NOT: crash-skipped-bodies-template-inst.cpp:7:{{[0-9]+}}: warning: using the result of an assignment as a condition without parentheses
+      // CHECK-NOT: crash-skipped-bodies-template-inst.cpp:7:{{[0-9]+}}: warning: converting the result of an assignment to bool
       return this;
     }
   };
@@ -14,7 +14,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is not skipped.
-  // CHECK: crash-skipped-bodies-template-inst.cpp:15:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: crash-skipped-bodies-template-inst.cpp:15:9: warning: converting the result of an assignment to bool
   return impl();
 }
 
Index: test/CodeCompletion/skip-auto-funcs.cpp
===================================================================
--- test/CodeCompletion/skip-auto-funcs.cpp
+++ test/CodeCompletion/skip-auto-funcs.cpp
@@ -7,7 +7,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is not skipped.
-  // CHECK: 8:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: 8:9: warning: converting the result of an assignment to bool
   return 1;
 }
 
@@ -16,7 +16,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is not skipped.
-  // CHECK: 17:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: 17:9: warning: converting the result of an assignment to bool
   return 1;
 }
 
@@ -25,7 +25,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is skipped.
-  // CHECK-NOT: 26:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK-NOT: 26:9: warning: converting the result of an assignment to bool
   return 1;
 };
 
@@ -33,7 +33,7 @@
   int x;
   if (x = 10) {}
   // This could potentially be skipped, but it isn't at the moment.
-  // CHECK: 34:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: 34:9: warning: converting the result of an assignment to bool
   return 1;
 };
 
@@ -42,7 +42,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is not skipped.
-  // CHECK: 43:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: 43:9: warning: converting the result of an assignment to bool
   return T();
 }
 
@@ -51,7 +51,7 @@
   int x;
   if (x = 10) {}
   // Check that this function is not skipped.
-  // CHECK: 52:9: warning: using the result of an assignment as a condition without parentheses
+  // CHECK: 52:9: warning: converting the result of an assignment to bool
   return 1;
 }
 
Index: test/Modules/diag-pragma.c
===================================================================
--- test/Modules/diag-pragma.c
+++ test/Modules/diag-pragma.c
@@ -6,7 +6,7 @@
 @import diag_pragma;
 
 int foo(int x) {
-  if (x = DIAG_PRAGMA_MACRO) // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (x = DIAG_PRAGMA_MACRO) // expected-warning {{converting the result of an assignment to bool}} \
                              // expected-note {{place parentheses}} expected-note {{use '=='}}
     return 0;
   return 1;
Index: test/Modules/diag-pragma.cpp
===================================================================
--- test/Modules/diag-pragma.cpp
+++ test/Modules/diag-pragma.cpp
@@ -40,7 +40,7 @@
 
   void("bar" + x);
 
-  if (x = DIAG_PRAGMA_MACRO) // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (x = DIAG_PRAGMA_MACRO) // expected-warning {{converting the result of an assignment to bool}} \
                              // expected-note {{place parentheses}} expected-note {{use '=='}}
     return 0;
   return 1;
Index: test/Sema/assigment-in-bool-context.c
===================================================================
--- test/Sema/assigment-in-bool-context.c
+++ test/Sema/assigment-in-bool-context.c
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -Wassigment-in-bool-context -fsyntax-only -verify %s
+// RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify %s
+
+_Bool warn1(int x) {
+  return x = 0;
+}
+
+_Bool warn2(int x, _Bool a, _Bool b) {
+  return x = 0 || (a && b);
+}
+
+_Bool warn3(int x, _Bool a) {
+  return x = 0 || a;
+}
+
+_Bool warn4(int x) {
+  return _Bool(x = 0); // expected-error {{expected expression}}
+}
+
+int warn5(int x) {
+  return _Bool(x = 0); // expected-error {{expected expression}}
+}
+
+_Bool warn6(int x, int a) {
+  return x = a;
+}
+
+int nowarn1(int x) {
+  return (x = 0);
+}
+
+int nowarn2(int x) {
+  return x = 0;
+}
+
+int nowarn3(int x) {
+  return x == 0;
+}
+
+_Bool nowarn4(int x) {
+  return x == 0;
+}
Index: test/Sema/parentheses.c
===================================================================
--- test/Sema/parentheses.c
+++ test/Sema/parentheses.c
@@ -4,7 +4,7 @@
 // Test the various warnings under -Wparentheses
 void if_assign(void) {
   int i;
-  if (i = 4) {} // expected-warning {{assignment as a condition}} \
+  if (i = 4) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{place parentheses around the assignment to silence this warning}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:7-[[@LINE-3]]:7}:"("
@@ -145,6 +145,3 @@
   (void)(x + y > 0 ? 1 : 2); // no warning
   (void)(x + (y > 0) ? 1 : 2); // expected-warning {{operator '?:' has lower precedence than '+'}} expected-note 2{{place parentheses}}
 }
-
-// RUN: not %clang_cc1 -fsyntax-only -Wparentheses -Werror -fdiagnostics-show-option %s 2>&1 | FileCheck %s -check-prefix=CHECK-FLAG
-// CHECK-FLAG: error: using the result of an assignment as a condition without parentheses [-Werror,-Wparentheses]
Index: test/SemaCXX/assigment-in-bool-context.cpp
===================================================================
--- test/SemaCXX/assigment-in-bool-context.cpp
+++ test/SemaCXX/assigment-in-bool-context.cpp
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -Wassigment-in-bool-context -fsyntax-only -verify %s
+// RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify %s
+
+bool warn1(int x) {
+  return x = 0; // expected-warning {{converting the result of an assignment to bool}}
+                // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+bool warn2(int x, bool a, bool b) {
+  return x = 0 || (a && b); // expected-warning {{converting the result of an assignment to bool}}
+                            // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                            // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+bool warn3(int x, bool a) {
+  return x = 0 || a; // expected-warning {{converting the result of an assignment to bool}}
+                     // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                     // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+bool warn4(int x) {
+  return bool(x = 0); // expected-warning {{converting the result of an assignment to bool}}
+                      // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                      // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+int warn5(int x) {
+  return bool(x = 0); // expected-warning {{converting the result of an assignment to bool}}
+                      // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                      // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+bool warn6(int x, int a) {
+  return x = a; // expected-warning {{converting the result of an assignment to bool}}
+                // expected-note@-1 {{place parentheses around the assignment to silence this warning}}
+                // expected-note@-2 {{use '==' to turn this assignment into an equality comparison}}
+}
+
+int nowarn1(int x) {
+  return (x = 0);
+}
+
+int nowarn2(int x) {
+  return x = 0;
+}
+
+int nowarn3(int x) {
+  return x == 0;
+}
+
+bool nowarn4(int x) {
+  return x == 0;
+}
Index: test/SemaCXX/warn-assignment-condition.cpp
===================================================================
--- test/SemaCXX/warn-assignment-condition.cpp
+++ test/SemaCXX/warn-assignment-condition.cpp
@@ -12,41 +12,41 @@
   A a, b;
 
   // With scalars.
-  if (x = 7) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (x = 7) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   if ((x = 7)) {}
   do {
-  } while (x = 7); // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  } while (x = 7); // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   do {
   } while ((x = 7));
-  while (x = 7) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  while (x = 7) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
 
   while ((x = 7)) {}
-  for (; x = 7; ) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  for (; x = 7; ) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   for (; (x = 7); ) {}
 
-  if (p = p) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (p = p) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   if ((p = p)) {}
   do {
-  } while (p = p); // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  } while (p = p); // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   do {
   } while ((p = p));
-  while (p = p) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  while (p = p) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   while ((p = p)) {}
-  for (; p = p; ) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  for (; p = p; ) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   for (; (p = p); ) {}
@@ -58,51 +58,51 @@
   while (A y = a) {}
 
   // With temporaries.
-  if (x = (b+b).foo()) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (x = (b+b).foo()) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   if ((x = (b+b).foo())) {}
   do {
-  } while (x = (b+b).foo()); // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  } while (x = (b+b).foo()); // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   do {
   } while ((x = (b+b).foo()));
-  while (x = (b+b).foo()) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  while (x = (b+b).foo()) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   while ((x = (b+b).foo())) {}
-  for (; x = (b+b).foo(); ) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  for (; x = (b+b).foo(); ) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   for (; (x = (b+b).foo()); ) {}
 
   // With a user-defined operator.
-  if (a = b + b) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (a = b + b) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   if ((a = b + b)) {}
   do {
-  } while (a = b + b); // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  } while (a = b + b); // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   do {
   } while ((a = b + b));
-  while (a = b + b) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  while (a = b + b) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   while ((a = b + b)) {}
-  for (; a = b + b; ) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  for (; a = b + b; ) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '==' to turn this assignment into an equality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
   for (; (a = b + b); ) {}
 
   // Compound assignments.
-  if (x |= 2) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (x |= 2) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '!=' to turn this compound assignment into an inequality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
 
-  if (a |= b) {} // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (a |= b) {} // expected-warning {{converting the result of an assignment to bool}} \
                 // expected-note{{use '!=' to turn this compound assignment into an inequality comparison}} \
   // expected-note{{place parentheses around the assignment to silence this warning}}
 
Index: test/SemaObjC/idiomatic-parentheses.m
===================================================================
--- test/SemaObjC/idiomatic-parentheses.m
+++ test/SemaObjC/idiomatic-parentheses.m
@@ -27,7 +27,7 @@
   if (self = [self initWithInt: i]) {
   }
   // rdar://11066598
-  if (self.uid = 100) { // expected-warning {{using the result of an assignment as a condition without parentheses}} \
+  if (self.uid = 100) { // expected-warning {{converting the result of an assignment to bool}} \
                         // expected-note {{place parentheses around the assignment to silence this warning}} \
                         // expected-note {{use '==' to turn this assignment into an equality comparison}}
         // ...
Index: test/SemaObjC/self-assign.m
===================================================================
--- test/SemaObjC/self-assign.m
+++ test/SemaObjC/self-assign.m
@@ -6,7 +6,7 @@
 - (id):(int)x :(int)y {
     int z;
     // <rdar://problem/8939352>
-    if (self = [self :x :y]) {} // expected-warning{{using the result of an assignment as a condition without parentheses}} \
+    if (self = [self :x :y]) {} // expected-warning{{converting the result of an assignment to bool}} \
     // expected-note{{use '==' to turn this assignment into an equality comparison}} \
     // expected-note{{place parentheses around the assignment to silence this warning}}
     return self;