Generalize the closure work from yesterday, enough to fix:

rdar://17687826 - QoI: error message when reducing to an untyped dictionary isn't helpful

Author: lattner

lib/Sema/CSDiag.cpp

@@ -6156,7 +6156,9 @@ diagnoseAmbiguousMultiStatementClosure(ClosureExpr *closure) {
     return false;
 
   auto closureType = closure->getType()->getAs<AnyFunctionType>();
-  if (!closureType || !isUnresolvedOrTypeVarType(closureType->getResult()))
+  if (!closureType ||
+      !(closureType->getResult()->hasUnresolvedType() ||
+        closureType->getResult()->hasTypeVariable()))
     return false;
 
   // Okay, we have a multi-statement closure expr that has no inferred result,

test/Constraints/subscript.swift

@@ -72,7 +72,7 @@ let _ = 1["1"]  // expected-error {{ambiguous use of 'subscript'}}
 
 
 // rdar://17687826 - QoI: error message when reducing to an untyped dictionary isn't helpful
-let squares = [ 1, 2, 3 ].reduce([:]) { (dict, n) in // expected-error {{expression type '[_ : _]' is ambiguous without more context}}
+let squares = [ 1, 2, 3 ].reduce([:]) { (dict, n) in // expected-error {{unable to infer complex closure return type; add explicit type to disambiguate}} {{51-51=-> [_ : _] }}
   var dict = dict
   dict[n] = n * n
   return dict

test/Constraints/tuple.swift

@@ -193,9 +193,9 @@ extension r25271859 {
 
 func f(a : r25271859<(Float, Int)>) {
   a.map { $0.0 }
-    .andThen { _ in   // expected-error {{generic parameter 'U' could not be inferred}}
+    .andThen { _ in   // expected-error {{unable to infer complex closure return type; add explicit type to disambiguate}} {{18-18=-> r25271859<String> }}
       print("hello") // comment this out and it runs, leave any form of print in and it doesn't
-      return Task<String>()
+      return r25271859<String>()
   }
 }