[Sema] Respect other ApplyExprs’ call parens

PreCheckExpression was not treating the implicit call parens on unary or binary operator applications like the explicit parens on CallExpr applications. Now it will. This prevents various forms of mischief, like having them subsumed into a TypeExpr.

Author: beccadax

lib/Sema/TypeCheckConstraints.cpp

@@ -986,8 +986,10 @@ namespace {
 
     std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
       // If this is a call, record the argument expression.
-      if (auto call = dyn_cast<CallExpr>(expr)) {
-        CallArgs.insert(call->getArg());
+      if (auto call = dyn_cast<ApplyExpr>(expr)) {
+        if (!isa<SelfApplyExpr>(expr)) {
+          CallArgs.insert(call->getArg());
+        }
       }
 
       // If this is an unresolved member with a call argument (e.g.,