Set symbol/flags only on (fresh) object spreads

If you spread any into an object, the type is any, which should not be
changed.

Author: sandersn

src/compiler/checker.ts

@@ -11638,8 +11638,11 @@ namespace ts {
                 if (propertiesArray.length > 0) {
                     spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
                 }
-                spread.flags |= propagatedFlags;
-                spread.symbol = node.symbol;
+                if (spread.flags & TypeFlags.Object) {
+                    // only set the symbol and flags if this is a (fresh) object type
+                    spread.flags |= propagatedFlags;
+                    spread.symbol = node.symbol;
+                }
                 return spread;
             }