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Rollup merge of #135794 - estebank:non-exhaustive-dfv-ctor, r=jieyouxu

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Detect missing fields with default values and suggest `..`

When a struct ctor use has missing fields, if all those missing fields have defaults, suggest `..`:

```
error[E0063]: missing fields `field1` and `field2` in initializer of `S`
  --> $DIR/non-exhaustive-ctor.rs:16:13
   |
LL |     let _ = S { field: () };
   |             ^ missing `field1` and `field2`
   |
help: all remaining fields have default values, you can use those values with `..`
   |
LL |     let _ = S { field: (), .. };
   |                          ++++
```
This commit is contained in:
Matthias Krüger 2025-01-22 20:37:26 +01:00 • committed by GitHub
commit 3b36879203
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30
compiler/rustc_hir_typeck/src/expr.rs
View file

@ -2349,6 +2349,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.report_missing_fields(
adt_ty,
path_span,
expr.span,
remaining_fields,
variant,
hir_fields,
@ -2386,6 +2387,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
&self,
adt_ty: Ty<'tcx>,
span: Span,
full_span: Span,
remaining_fields: UnordMap<Ident, (FieldIdx, &ty::FieldDef)>,
variant: &'tcx ty::VariantDef,
hir_fields: &'tcx [hir::ExprField<'tcx>],
@ -2425,6 +2427,34 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
err.span_label(span, format!("missing {remaining_fields_names}{truncated_fields_error}"));
if remaining_fields.items().all(|(_, (_, field))| field.value.is_some())
&& self.tcx.sess.is_nightly_build()
{
let msg = format!(
"all remaining fields have default values, {you_can} use those values with `..`",
you_can = if self.tcx.features().default_field_values() {
"you can"
} else {
"if you added `#![feature(default_field_values)]` to your crate you could"
},
);
if let Some(hir_field) = hir_fields.last() {
err.span_suggestion_verbose(
hir_field.span.shrink_to_hi(),
msg,
", ..".to_string(),
Applicability::MachineApplicable,
);
} else if hir_fields.is_empty() {
err.span_suggestion_verbose(
span.shrink_to_hi().with_hi(full_span.hi()),
msg,
" { .. }".to_string(),
Applicability::MachineApplicable,
);
}
}
if let Some(hir_field) = hir_fields.last() {
self.suggest_fru_from_range_and_emit(hir_field, variant, args, err);
} else {