Sema: Fix another crash with tuple to Any conversion

An earlier patch fixed the case where some tuple elements
were lvalue types. However this only looked into tuples
nested one level deep, when a more correct fix checks the
lvalue recursive property of the type.

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -4748,31 +4748,10 @@ Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
                                       cs.getType(result)));
   }
 
-  // If the type we are trying to coerce is a tuple, let's look through
-  // its elements to see if there are any LValue types present, such requires
-  // load or address-of operation first before proceeding with erasure.
+  // Load tuples with lvalue elements.
   if (auto tupleType = fromType->getAs<TupleType>()) {
-    bool coerceToRValue = false;
-    for (auto element : tupleType->getElements()) {
-      if (element.getType()->is<LValueType>()) {
-        coerceToRValue = true;
-        break;
-      }
-    }
-
-    // Tuple has one or more LValue types associated with it,
-    // which requires coercion to RValue, let's perform it here by creating
-    // new tuple type with LValue(s) stripped off and coercing
-    // expression to that type, which would do required transformation.
-    if (coerceToRValue) {
-      SmallVector<TupleTypeElt, 2> elements;
-      for (auto &element : tupleType->getElements())
-        elements.push_back(TupleTypeElt(element.getType()->getRValueType(),
-                                        element.getName(),
-                                        element.getParameterFlags()));
-
-      // New type is guaranteed to be a tuple because source type is one.
-      auto toTuple = TupleType::get(elements, ctx)->castTo<TupleType>();
+    if (tupleType->isLValueType()) {
+      auto toTuple = tupleType->getRValueType()->castTo<TupleType>();
       SmallVector<int, 4> sources;
       SmallVector<unsigned, 4> variadicArgs;
       bool failed = computeTupleShuffle(tupleType, toTuple,

test/Constraints/tuple.swift

@@ -202,3 +202,14 @@ func f(a : r25271859<(Float, Int)>) {
   }
 }
 
+// LValue to rvalue conversions.
+
+func takesRValue(_: (Int, (Int, Int))) {}
+func takesAny(_: Any) {}
+
+var x = 0
+var y = 0
+
+let _ = (x, (y, 0))
+takesRValue((x, (y, 0)))
+takesAny((x, (y, 0)))