2f8d359f
by Simon Jakobi at 2026-06-09T12:48:19+02:00
Report related locations textually when carets are off
Related locations were previously visible only as carets. Carets are
optional (-fno-diagnostics-show-caret) and some spans have no source to
display (GHCi input, TH-generated code, or code remapped by a LINE pragma
to a file we can't read), so in those cases the extra locations vanished.
decorateDiagnostic now lists, under an "At:" heading printed between the
message and the caret snippets, every location that is not shown as a
caret -- including the primary span, so the list is a complete set of the
locations involved. Each location is shown either as a caret or in the
"At:" list. getCaretDiagnostics takes the show-caret flag and returns the
real spans that got *no* caret (sorted and deduped), so the list covers
exactly the spans the carets missed and the carets-off case is handled in
one place; the rendering splits each span into 'Either SDoc RealSrcSpan'
via partitionEithers. The Diagnostic GhciMessage instance now forwards
diagnosticRelatedLocations, which it previously dropped.
Locations are compared and deduped by their real span, which ignores the
BufSpan: a duplicate export's related span often differs from the primary
only in its BufSpan, which would otherwise be listed twice or mistaken for
a location beyond the primary. A list naming only the primary is dropped,
since the message header already states it.
The now-redundant location prose is removed from TcRnBindingNameConflict
("Bound at:") and TcRnDuplicateDecls ("Declared at:"), and
TcRnDuplicateNamedDefaultExport is reworded (its two export items are
always identical). TcRnDuplicateExport is left untouched.
The single-span getCaretDiagnostic lost its only caller in this rework, so
it is dropped along with its exports and .hs-boot declaration.
A new test, MultiCaretFallback, exercises a single diagnostic whose
related locations are split between carets and the "At:" fallback.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>