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Merged
merged 1 commit into from
Oct 27, 2025
Merged

More intuitive error when using self to instantiate tuple struct with private field #147478

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101 changes: 57 additions & 44 deletions compiler/rustc_resolve/src/late/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -180,6 +180,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
let mut expected = source.descr_expected();
let path_str = Segment::names_to_string(path);
let item_str = path.last().unwrap().ident;

if let Some(res) = res {
BaseError {
msg: format!("expected {}, found {} `{}`", expected, res.descr(), path_str),
Expand Down Expand Up @@ -821,12 +822,18 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
args_snippet = snippet;
}

err.span_suggestion(
call_span,
format!("try calling `{ident}` as a method"),
format!("self.{path_str}({args_snippet})"),
Applicability::MachineApplicable,
);
if let Some(Res::Def(DefKind::Struct, def_id)) = res {
self.update_err_for_private_tuple_struct_fields(err, &source, def_id);
err.note("constructor is not visible here due to private fields");
} else {
err.span_suggestion(
call_span,
format!("try calling `{ident}` as a method"),
format!("self.{path_str}({args_snippet})"),
Applicability::MachineApplicable,
);
}

return (true, suggested_candidates, candidates);
}
}
Expand Down Expand Up @@ -1611,6 +1618,47 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
}
}

fn update_err_for_private_tuple_struct_fields(
&mut self,
err: &mut Diag<'_>,
source: &PathSource<'_, '_, '_>,
def_id: DefId,
) -> Option<Vec<Span>> {
match source {
// e.g. `if let Enum::TupleVariant(field1, field2) = _`
PathSource::TupleStruct(_, pattern_spans) => {
err.primary_message(
"cannot match against a tuple struct which contains private fields",
);

// Use spans of the tuple struct pattern.
Some(Vec::from(*pattern_spans))
}
// e.g. `let _ = Enum::TupleVariant(field1, field2);`
PathSource::Expr(Some(Expr {
kind: ExprKind::Call(path, args),
span: call_span,
..
})) => {
err.primary_message(
"cannot initialize a tuple struct which contains private fields",
);
self.suggest_alternative_construction_methods(
def_id,
err,
path.span,
*call_span,
&args[..],
);
// Use spans of the tuple struct definition.
self.r
.field_idents(def_id)
.map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
}
_ => None,
}
}

/// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
/// function.
/// Returns `true` if able to provide context-dependent help.
Expand Down Expand Up @@ -1942,42 +1990,6 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
return true;
};

let update_message =
|this: &mut Self, err: &mut Diag<'_>, source: &PathSource<'_, '_, '_>| {
match source {
// e.g. `if let Enum::TupleVariant(field1, field2) = _`
PathSource::TupleStruct(_, pattern_spans) => {
err.primary_message(
"cannot match against a tuple struct which contains private fields",
);

// Use spans of the tuple struct pattern.
Some(Vec::from(*pattern_spans))
}
// e.g. `let _ = Enum::TupleVariant(field1, field2);`
PathSource::Expr(Some(Expr {
kind: ExprKind::Call(path, args),
span: call_span,
..
})) => {
err.primary_message(
"cannot initialize a tuple struct which contains private fields",
);
this.suggest_alternative_construction_methods(
def_id,
err,
path.span,
*call_span,
&args[..],
);
// Use spans of the tuple struct definition.
this.r
.field_idents(def_id)
.map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
}
_ => None,
}
};
let is_accessible = self.r.is_accessible_from(ctor_vis, self.parent_scope.module);
if let Some(use_span) = self.r.inaccessible_ctor_reexport.get(&span)
&& is_accessible
Expand Down Expand Up @@ -2006,13 +2018,14 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
Applicability::MachineApplicable,
);
}
update_message(self, err, &source);
self.update_err_for_private_tuple_struct_fields(err, &source, def_id);
}
if !is_expected(ctor_def) || is_accessible {
return true;
}

let field_spans = update_message(self, err, &source);
let field_spans =
self.update_err_for_private_tuple_struct_fields(err, &source, def_id);

if let Some(spans) =
field_spans.filter(|spans| spans.len() > 0 && fields.len() == spans.len())
Expand Down
16 changes: 16 additions & 0 deletions tests/ui/resolve/private-constructor-self-issue-147343.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
mod m {
pub struct S(crate::P);
}

use m::S;

struct P;

impl P {
fn foo(self) {
S(self);
//~^ ERROR cannot initialize a tuple struct which contains private fields [E0423]
}
}

fn main() {}
11 changes: 11 additions & 0 deletions tests/ui/resolve/private-constructor-self-issue-147343.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
error[E0423]: cannot initialize a tuple struct which contains private fields
--> $DIR/private-constructor-self-issue-147343.rs:11:9
|
LL | S(self);
| ^
|
= note: constructor is not visible here due to private fields

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0423`.
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