[E0635] Use of Unknown feature.

[MahadMuhammad]

Use of Unknown feature - E0635

Added ErrorCode support for use of unknown
feature.

---

Code Tested:

// ErrorCode - E0635
#![feature(AA)] //{ dg-error "unknown feature .AA." }
#![feature(iamcrabby)] // { dg-error "unknown feature .iamcrabby." }
#![feature(nonexistent_gccrs_feature)] // { dg-error "unknown feature .nonexistent_gccrs_feature." }

fn main() {}

---

Output:

➜  gccrs-build gcc/crab1 /home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/feature.rs
/home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/feature.rs:1:12: error: unknown feature ‘AA’ [E0635]
    1 | #![feature(AA)] //{ dg-error "unknown feature .AA." }
      |            ^~
/home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/feature.rs:2:12: error: unknown feature ‘iamcrabby’ [E0635]
    2 | #![feature(iamcrabby)] // { dg-error "unknown feature .iamcrabby." }
      |            ^~~~~~~~~
/home/mahad/Desktop/mahad/gccrs/gcc/testsuite/rust/compile/feature.rs:3:12: error: unknown feature ‘asm’ [E0635]
    3 | #![feature(asm)] // { dg-error "unknown feature .asm." }
      |            ^~~

Analyzing compilation unit

Time variable                                   usr           sys          wall           GGC
 TOTAL                              :   0.00          0.00          0.00          146k
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --enable-checking=release to disable checks.

---

gcc/rust/ChangeLog:

* checks/errors/rust-feature-gate.cc (FeatureGate::check): errorcode support for unknown feature.

gcc/testsuite/ChangeLog:

* rust/compile/feature.rs: Added new unknown feature.

---

[MahadMuhammad]

Should I also raise issue for this also E0554?. Seen in godbolt

[CohenArthur]

Looks good to me! Thank you!