Remove dead code from compiletest::json

[pierwill]

Currently getting a dead code warning on master. Might make sense to remove.

[rust-highfive]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

Are you compiling with a custom bootstrap compiler? I would have expected the warning to be caught in CI...

[pierwill]

This came up when doing rustc dev work, so probably yes.

[pierwill]

With current nightly:

cd src/tools/compiletest
cargo c
    Checking compiletest v0.0.0 (repos/rust/src/tools/compiletest)
warning: field is never read: `explanation`
  --> src/tools/compiletest/src/json.rs:78:5
   |
78 |     explanation: Option<String>,
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

warning: `compiletest` (bin "compiletest") generated 1 warning
    Finished dev [unoptimized] target(s) in 27.81s

[Mark-Simulacrum]

Oh, it's not generally expected that you'd try to build tools by hand like that -- we only verify building against the beta compiler in src/stage0.json, which is automatically provisioned by x.py for you.

I'll r+ this in the meantime, though, since it seems like a nice cleanup regardless.

@bors r+ rollup

[bors]

📌 Commit b87a0b0 has been approved by Mark-Simulacrum