[CSApply] shouldForceUnwrapResult() should return false when we don't have an disjunction choice

This will only be false if we have an IUO method call wrapped in parens (like '(s.foo)()'), so assert that the type is a function type as well

Author: theblixguy

lib/Sema/CSApply.cpp

@@ -2266,6 +2266,18 @@ namespace {
       if (!choice.isImplicitlyUnwrappedValueOrReturnValue())
         return false;
 
+      // If we have an IUO function call and don't have a disjunction choice,
+      // then it means we didn't create a disjunction because the call was
+      // wrapped in parens (i.e. '(s.returnsAnIUO)()') and so there's no
+      // need to force unwrap.
+      if (!solution.DisjunctionChoices.count(
+              cs.getConstraintLocator(locator))) {
+        auto type = choice.getDecl()->getInterfaceType();
+        assert((type && type->is<AnyFunctionType>()) &&
+               "expected a function type");
+        return false;
+      }
+
       auto *choiceLocator = cs.getConstraintLocator(locator.withPathElement(
           ConstraintLocator::ImplicitlyUnwrappedDisjunctionChoice));