bjoernager/rust
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Suggest accessing field when code compiles with it

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This commit is contained in:
Hirochika Matsumoto 2021-01-29 05:43:35 +09:00
parent e32f372c42
commit 9e4ed337c7
3 changed files with 75 additions and 0 deletions
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41
compiler/rustc_infer/src/infer/error_reporting/mod.rs
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@ -1661,6 +1661,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
debug!("exp_found {:?} terr {:?}", exp_found, terr);
if let Some(exp_found) = exp_found {
self.suggest_as_ref_where_appropriate(span, &exp_found, diag);
self.suggest_field_where_appropriate(cause, &exp_found, diag);
self.suggest_await_on_expect_found(cause, span, &exp_found, diag);
}
@ -1819,6 +1820,46 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
}
fn suggest_field_where_appropriate(
&self,
cause: &ObligationCause<'tcx>,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut DiagnosticBuilder<'tcx>,
) {
debug!("suggest_field_where_appropriate(cause={:?}, exp_found={:?})", cause, exp_found);
if let ty::Adt(expected_def, expected_substs) = exp_found.expected.kind() {
if expected_def.is_enum() {
return;
}
if let Some((name, ty)) = expected_def
.non_enum_variant()
.fields
.iter()
.filter(|field| field.vis.is_accessible_from(field.did, self.tcx))
.map(|field| (field.ident.name, field.ty(self.tcx, expected_substs)))
.inspect(|(name, ty)| {
debug!("suggest_field_where_appropriate: name={:?}, ty={:?}", name, ty)
})
.find(|(_, ty)| ty::TyS::same_type(ty, exp_found.found))
{
if let ObligationCauseCode::Pattern { span: Some(span), .. } = cause.code {
if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
diag.span_suggestion(
span,
&format!(
"you might have meant to use field `{}` of type `{}`",
name, ty
),
format!("{}.{}", snippet, name),
Applicability::MaybeIncorrect,
);
}
}
}
}
}
/// When encountering a case where `.as_ref()` on a `Result` or `Option` would be appropriate,
/// suggests it.
fn suggest_as_ref_where_appropriate(