[E0308] mismatch types on both sides of assignment Operator

[MahadMuhammad]

Mismatch types - E0308

• This errorcode emits when there are mismatch types between lhs & rhs of assignment operator & refactored message.

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Code Tested from E0308

// ErrorCode::E0308
#![allow(unused)]
fn main() {
    fn plus_one(x: i32) -> i32 { 
        x + 1 
    }
    plus_one("Not a number");       // { dg-error "mismatched types, expected .i32. got .& str." }
    let x: f32 = "Not a float";     // { dg-error "mismatched types, expected .f32. got .& str." }
}

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Output:

➜  gccrs-build gcc/crab1 /home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/mismatched-types.rs
/home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/mismatched-types.rs:7:14: error: mismatched types, expected ‘i32’ got ‘& str’ [E0308]
    4 |     fn plus_one(x: i32) -> i32 {
      |                 ~
......
    7 |     plus_one("Not a number");       // { dg-error "mismatched types, expected .i32. got .& str." }
      |              ^~~~~~~~~~~~~
/home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/mismatched-types.rs:8:5: error: mismatched types, expected ‘f32’ got ‘& str’ [E0308]
    8 |     let x: f32 = "Not a float";     // { dg-error "mismatched types, expected .f32. got .& str." }
      |     ^~~    ~~~   ~~~~~~~~~~~~

Analyzing compilation unit

Time variable                                   usr           sys          wall           GGC
 phase setup                        :   0.00 (  0%)   0.00 (  0%)   0.01 (100%)   138k ( 95%)
 TOTAL                              :   0.00          0.00          0.01          146k
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --enable-checking=release to disable checks.

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There are no previous running test cases for this.

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gcc/rust/ChangeLog:

* typecheck/rust-unify.cc (UnifyRules::emit_type_mismatch): refactored & called error function.

gcc/testsuite/ChangeLog:

* rust/compile/mismatched-types.rs: New test from rustc.

[CohenArthur]

Slight nit but looks good otherwise! Thank you!

[MahadMuhammad]

I also updated the test case now, Thanks for review :)

[MahadMuhammad]

@CohenArthur Sorry for delay as this message was used in many places in our test suite.