lean4-htt/stage0
Leonardo de Moura 9f49ea63e2
feat: add backward.isDefEq.respectTransparency.types option (#13280)
This PR adds a new option `backward.isDefEq.respectTransparency.types`
that controls the transparency used when checking whether the type of a
metavariable matches the type of the term being assigned to it during
`checkTypesAndAssign`. Previously, this check always bumped transparency
to `.default` (via `withInferTypeConfig`), which is overly permissive.
The new option uses `.instances` transparency instead (via
`withImplicitConfig`), matching the behavior already used for implicit
arguments.

The option defaults to `false` (preserving old behavior) until stage0 is
updated and breakage is assessed. If
`backward.isDefEq.respectTransparency` (already in v4.29) is set to
`false`, then `backward.isDefEq.respectTransparency.types` is
automatically treated as `false` too.

When `diagnostics` is enabled, a trace message is emitted if the
stricter transparency fails but `.default` would have succeeded, helping
identify affected code. To investigate failures when enabling
`backward.isDefEq.respectTransparency.types`, use:

```
set_option diagnostics true
set_option trace.diagnostics true
```

Also renames `withInstanceConfig` to `withImplicitConfig` since it now
serves implicit argument and type checking, not just instances.
Registers the `diagnostics` trace class in `CoreM`.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-04 18:05:33 +00:00
..
src feat: add backward.isDefEq.respectTransparency.types option (#13280) 2026-04-04 18:05:33 +00:00
stdlib chore: update stage0 2026-04-02 10:20:07 +00:00