Dana Jansens 7beb29f8b2 Use a fallback loc for diagnostics generated on canonical insts (#7967) ...

We allow using `InstId` as a `LocId` for diagnostics, which works great
in `handle_*` functions, where we are working with non-canonical insts.
And convert and pattern matching often are given non-canonical insts,
which they can use, or pull apart to find some other inst, and use those
as a location for diagnostics. However these operations can also be
called with canonical insts, which have no location. In that case if we
need to diagnose an error, it ends up not being attached to any code at
all. Since we always have a `LocId` somewhere up the call stack, pass it
along and in these places that handle canonical instructions too, use
`GetInstLocationOrFallback()` to get a valid location for diagnostics.

This is also similar to what eval does with its fallback `LocId`.

The result is that many diagnostics now have a location where they had
none before. It also means some insts don't get `<elided>` in formatted
semir for not having a location at all and thus not being in range.

2026-10-15 19:03:10 +00:00

..

basics.carbon

Render diagnostics through the terminal library (#7683)

2026-10-15 06:08:57 +00:00

bound_values.carbon

Render diagnostics through the terminal library (#7683)

2026-10-15 06:08:57 +00:00

element_mismatches.carbon

Render diagnostics through the terminal library (#7683)

2026-10-15 06:08:57 +00:00

import.carbon

Defer evaluation of witnesses substituted while identifying a facet type (#7930)

2026-10-14 14:12:56 +00:00

index_not_literal.carbon

Render diagnostics through the terminal library (#7683)

2026-10-15 06:08:57 +00:00

init_dependent_bound.carbon

Use a fallback loc for diagnostics generated on canonical insts (#7967)

2026-10-15 19:03:10 +00:00