Add support for mut bindings in function arguments · BurntSushi/quickcheck#269

2021-01-12T13:46:30.000Z

I noticed that this works: ```rust fn check_int_slices(v: HashSet , lens: Vec ) -> bool { let mut lens = lens; ... } ``` but this doesn't: ```rust fn check_int_slices(v: HashSet , mut lens: Vec ) -> bool { ... } ``` Error: ```rust error: no rules expected the token `lens` --> src/lib.rs:797:50 | 797 | fn check_int_slices(v: HashSet , mut lens: Vec ) -> bool { | ^^^^ no rules expected this token in macro call ```

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enhancementhelp wanted

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Description

I noticed that this works:

fn check_int_slices(v: HashSet<u64>, lens: Vec<usize>) -> bool {
    let mut lens = lens;
    ...
}

but this doesn't:

fn check_int_slices(v: HashSet<u64>, mut lens: Vec<usize>) -> bool {
    ...
}

Error:

error: no rules expected the token `lens`
   --> src/lib.rs:797:50
    |
797 |         fn check_int_slices(v: HashSet<u64>, mut lens: Vec<usize>) -> bool {
    |                                                  ^^^^ no rules expected this token in macro call

Contributor guide

Research direction: Examine the quickcheck macro definition to understand how it parses function arguments, then modify the pattern to accept 'mut' bindings.
Tech stack: rust
Domain: testing
Issue type: Feature
Difficulty: 3
Estimated time: 1-2 days
Activity status: Active
Clarity: Clear
Prerequisites: Rust
Newbie friendliness: 60

Repository metrics

Description

Contributor guide

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