Fixed 'kind' check in KeyPathExpr::Component constructor

Author: Toma91

include/swift/AST/Expr.h

@@ -4861,7 +4861,7 @@ class KeyPathExpr : public Expr {
                        Expr *indexExpr,
                        ArrayRef<Identifier> subscriptLabels,
                        ArrayRef<ProtocolConformanceRef> indexHashables,
-                       unsigned fieldNumber,
+                       unsigned tupleIndex,
                        Kind kind,
                        Type type,
                        SourceLoc loc);

lib/AST/Expr.cpp

@@ -2185,7 +2185,7 @@ KeyPathExpr::Component::Component(ASTContext *ctxForCopyingLabels,
                      Expr *indexExpr,
                      ArrayRef<Identifier> subscriptLabels,
                      ArrayRef<ProtocolConformanceRef> indexHashables,
-                     unsigned fieldNumber,
+                     unsigned tupleIndex,
                      Kind kind,
                      Type type,
                      SourceLoc loc)
@@ -2194,13 +2194,15 @@ KeyPathExpr::Component::Component(ASTContext *ctxForCopyingLabels,
 {
   assert(subscriptLabels.size() == indexHashables.size()
          || indexHashables.empty());
-  assert(subscriptLabels.empty() || fieldNumber == 0);
   SubscriptLabelsData = subscriptLabels.data();
   SubscriptHashableConformancesData = indexHashables.empty()
     ? nullptr : indexHashables.data();
+  
+  if (kind == Kind::TupleElement) {
+    assert(subscriptLabels.empty()
+           && "subscript labels not empty for tuple element");
 
-  if (subscriptLabels.empty()) {
-    TupleIndex = fieldNumber;
+    TupleIndex = tupleIndex;
   } else {
     SubscriptSize = subscriptLabels.size();
   }