Fix hole where missing_nullary_call wasn't diagnosed in ternary condition.

Author: Greg Titus

lib/Sema/CSDiagnostics.cpp

@@ -3168,6 +3168,14 @@ bool ContextualFailure::diagnoseConversionToBool() const {
     return true;
   }
 
+  if (auto fnType = getFromType()->getAs<FunctionType>()) {
+    if (fnType->getResult()->isBool() && fnType->getNumParams() == 0) {
+      emitDiagnostic(diag::missing_nullary_call, toType)
+          .fixItInsertAfter(getSourceRange().End, "()");
+      return true;
+    }
+  }
+
   return false;
 }
 

test/Constraints/ternary_expr.swift

@@ -59,6 +59,9 @@ _ = true ? x : 1.2 // expected-error {{result values in '? :' expression have mi
 _ = (x: true) ? true : false // expected-error {{cannot convert value of type '(x: Bool)' to expected condition type 'Bool'}}
 _ = (x: 1) ? true : false // expected-error {{cannot convert value of type '(x: Int)' to expected condition type 'Bool'}}
 
+func resultBool() -> Bool { true }
+_ = resultBool ? true : false // expected-error {{function produces expected type 'Bool'; did you mean to call it with '()'?}} {{15-15=()}}
+
 let ib: Bool! = false
 let eb: Bool? = .some(false)
 let conditional = ib ? "Broken" : "Heart" // should infer Bool!