Compile error if function args are mut

[jherman3]

This is a really cool macro!
I noticed that it doesn't work if we declare mut function args:

use cached::proc_macro::cached;

#[cached]
fn foo(mut x: i32) -> i32 {
    x += 1;
    x
}

This gives:

error: expected expression, found keyword `mut`
 --> src/bin/foo.rs:4:8
  |
4 | fn foo(mut x: i32) -> i32 {
  |        ^^^ expected expression

This works:

use cached::proc_macro::cached;

#[cached]
fn foo(x: i32) -> i32 {
    let mut x = x;
    x += 1;
    x
}

It's easy to work around but it feels like a parsing bug that the former doesn't work.

[jaemk]

yeah, I'm going to guess it's this line being naive

cached/cached_proc_macro/src/lib.rs

Line 93 in 4d7dea2

FnArg::Typed(pat_type) => pat_type.pat.clone(),

[jaemk]

This should be fixed now, released in 0.29.0

cached/tests/cached.rs

Lines 1144 to 1155 in e24d7a7

	#[cached]
	fn mutable_args(mut a: i32, mut b: i32) -> (i32, i32) {
	a += 1;
	b += 1;
	(a, b)
	}
	#[test]
	fn test_mutable_args() {
	assert_eq!((2, 2), mutable_args(1, 1));
	assert_eq!((2, 2), mutable_args(1, 1));
	}