Fix build after merging #35862

src/compiler/checker.ts

@@ -31622,7 +31622,7 @@ namespace ts {
                     const childSymbol = getSymbolAtLocation(childNode);
                     if (childSymbol && childSymbol === testedFunctionSymbol) {
                         // If the test was a simple identifier, the above check is sufficient
-                        if (isIdentifier(ifStatement.expression)) {
+                        if (isIdentifier(condExpr)) {
                             return true;
                         }
                         // Otherwise we need to ensure the symbol is called on the same target