Safety:
For a function-local variable, an expression with side-effects would be a call, including an indirect one with a member expression.
- If the call is function-local, it will be analyzed by the analyzer and inliner will not work.
- If the call is not a function-local one, it cannot modify the local variable.
- We don't need a list of bindings to check if an identifier is unresolved.
- Checking if an identifier is unresolved is now one CPU instruction.
- Previously it was one hashmap operation.
- This PR also improves performance, by removing the hashmaps mentioned above.
swc_ecma_minifier:
- `conditionals`: Preserve a conditional expression if test is not resolved.
- `unsafe_arrows`: Optimize an anonymous function expression as an arrow expression.
- `unsafe_methods`: Optimize a method property where the only statement is return to an arrow expression.
