Sema: Fix recently-introduced crash with diagnostics of inout parameters

Recently TupleTypeElt was changed to add an inout bit. It is no
longer valid to construct tuple types whose elements have InOutType,
and instead the flag on the element must be set instead.

Update diagnoseImplicitSelfErrors() for the new convention.

Fixes the only remaining crash in the test case from <rdar://19569255>,
but the original issue were fixed long ago.

Author: slavapestov

lib/Sema/CSDiag.cpp

@@ -4747,13 +4747,17 @@ static bool diagnoseImplicitSelfErrors(Expr *fnExpr, Expr *argExpr,
     // matches what the user actually wrote instead of what the typechecker
     // expects.
     SmallVector<TupleTypeElt, 4> elts;
-    for (auto *el : argTuple->getElements()) {
+    for (unsigned i = 0, e = argTuple->getNumElements(); i < e; ++i) {
       ConcreteDeclRef ref = nullptr;
+      auto *el = argTuple->getElement(i);
       auto typeResult =
         TC.getTypeOfExpressionWithoutApplying(el, CS.DC, ref);
       if (!typeResult)
         return false;
-      elts.push_back(typeResult);
+      auto flags = ParameterTypeFlags().withInOut(typeResult->is<InOutType>());
+      elts.push_back(TupleTypeElt(typeResult->getInOutObjectType(),
+                                  argTuple->getElementName(i),
+                                  flags));
     }
 
     argType = TupleType::get(elts, CS.getASTContext());

test/Constraints/members.swift

@@ -417,3 +417,15 @@ extension Array where Element == Int {
     // expected-error@-1 {{use of 'min' nearly matches global function 'min' in module 'Swift' rather than instance method 'min()'}}
   }
 }
+
+// Crash in diagnoseImplicitSelfErrors()
+
+struct Aardvark {
+  var snout: Int
+
+  mutating func burrow() {
+    dig(&snout, .y) // expected-error {{type 'Int' has no member 'y'}}
+  }
+
+  func dig(_: inout Int, _: Int) {}
+}