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resolve: Partially convert ambiguous_glob_imports lint into a hard error #149195

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resolve: Partially convert ambiguous_glob_imports lint into a hard error #149195

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2 changes: 0 additions & 2 deletions compiler/rustc_codegen_gcc/build_system/src/test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -886,8 +886,6 @@ fn valid_ui_error_pattern_test(file: &str) -> bool {
"type-alias-impl-trait/auxiliary/cross_crate_ice.rs",
"type-alias-impl-trait/auxiliary/cross_crate_ice2.rs",
"macros/rfc-2011-nicer-assert-messages/auxiliary/common.rs",
"imports/ambiguous-1.rs",
"imports/ambiguous-4-extern.rs",
"entry-point/auxiliary/bad_main_functions.rs",
]
.iter()
Expand Down
4 changes: 1 addition & 3 deletions compiler/rustc_lint_defs/src/builtin.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4622,7 +4622,7 @@ declare_lint! {
///
/// ### Example
///
/// ```rust,compile_fail
/// ```rust,ignore (needs extern crate)
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@mu001999 mu001999 May 17, 2026

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This example and the explanation below it are outdated. Is there a more suitable example that demonstrates the current lint behavior?

/// #![deny(ambiguous_glob_imports)]
/// pub fn foo() -> u32 {
/// use sub::*;
Expand All @@ -4638,8 +4638,6 @@ declare_lint! {
/// }
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// Previous versions of Rust compile it successfully because it
Expand Down
9 changes: 4 additions & 5 deletions compiler/rustc_resolve/src/build_reduced_graph.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
decl: Decl<'ra>,
) {
if let Err(old_decl) =
self.try_plant_decl_into_local_module(ident, orig_ident_span, ns, decl, false)
self.try_plant_decl_into_local_module(ident, orig_ident_span, ns, decl)
{
self.report_conflict(ident, ns, old_decl, decl);
}
Expand Down Expand Up @@ -87,13 +87,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
vis: Visibility<DefId>,
span: Span,
expansion: LocalExpnId,
ambiguity: Option<Decl<'ra>>,
ambiguity: Option<(Decl<'ra>, bool)>,
) {
let decl = self.arenas.alloc_decl(DeclData {
kind: DeclKind::Def(res),
ambiguity: CmCell::new(ambiguity),
// External ambiguities always report the `AMBIGUOUS_GLOB_IMPORTS` lint at the moment.
warn_ambiguity: CmCell::new(true),
initial_vis: vis,
ambiguity_vis_max: CmCell::new(None),
ambiguity_vis_min: CmCell::new(None),
Expand Down Expand Up @@ -392,7 +390,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
let ModChild { ident: _, res, vis, ref reexport_chain } = *ambig_child;
let span = child_span(self, reexport_chain, res);
let res = res.expect_non_local();
self.arenas.new_def_decl(res, vis, span, expansion, Some(parent.to_module()))
// External ambiguities always report the `AMBIGUOUS_GLOB_IMPORTS` lint at the moment.
(self.arenas.new_def_decl(res, vis, span, expansion, Some(parent.to_module())), true)
});

// Record primary definitions.
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_resolve/src/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1188,7 +1188,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
.emit()
}

fn def_path_str(&self, mut def_id: DefId) -> String {
pub(crate) fn def_path_str(&self, mut def_id: DefId) -> String {
// We can't use `def_path_str` in resolve.
let mut path = vec![def_id];
while let Some(parent) = self.tcx.opt_parent(def_id) {
Expand Down
166 changes: 82 additions & 84 deletions compiler/rustc_resolve/src/imports.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -382,11 +382,9 @@ fn remove_same_import<'ra>(d1: Decl<'ra>, d2: Decl<'ra>) -> (Decl<'ra>, Decl<'ra
assert_eq!(d1.span, d2.span);
if d1.ambiguity.get() != d2.ambiguity.get() {
assert!(d1.ambiguity.get().is_some());
assert!(d2.ambiguity.get().is_none());
}
// Visibility of the new import declaration may be different,
// because it already incorporates the visibility of the source binding.
// `warn_ambiguity` of a re-fetched glob can also change in both directions.
remove_same_import(d1_next, d2_next)
} else {
(d1, d2)
Expand Down Expand Up @@ -450,7 +448,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
self.arenas.alloc_decl(DeclData {
kind: DeclKind::Import { source_decl: decl, import },
ambiguity: CmCell::new(None),
warn_ambiguity: CmCell::new(false),
span: import.span,
initial_vis: vis.to_def_id(),
ambiguity_vis_max: CmCell::new(None),
Expand All @@ -460,14 +457,60 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
})
}

fn is_noise_0_7_0(&self, old_glob_decl: Decl<'ra>, glob_decl: Decl<'ra>) -> bool {
let DeclKind::Import { import: i1, .. } = glob_decl.kind else { unreachable!() };
let DeclKind::Import { import: i2, .. } = old_glob_decl.kind else { unreachable!() };
let [seg1, seg2] = &i1.module_path[..] else { return false };
if seg1.ident.name != kw::SelfLower || seg2.ident.name.as_str() != "perlin_surflet" {
return false;
}
let [seg1, seg2] = &i2.module_path[..] else { return false };
if seg1.ident.name != kw::SelfLower || seg2.ident.name.as_str() != "perlin" {
return false;
}
let Some(def_id1) = glob_decl.res().opt_def_id() else { return false };
let Some(def_id2) = old_glob_decl.res().opt_def_id() else { return false };
self.def_path_str(def_id1).ends_with("noise_fns::generators::perlin_surflet::Perlin")
&& self.def_path_str(def_id2).ends_with("noise_fns::generators::perlin::Perlin")
}

fn is_rustybuzz_0_4_0(&self, old_glob_decl: Decl<'ra>, glob_decl: Decl<'ra>) -> bool {
let DeclKind::Import { import: i1, .. } = glob_decl.kind else { unreachable!() };
let DeclKind::Import { import: i2, .. } = old_glob_decl.kind else { unreachable!() };
let [seg1, seg2] = &i1.module_path[..] else { return false };
if seg1.ident.name != kw::Super || seg2.ident.name.as_str() != "gsubgpos" {
return false;
}
let [seg1] = &i2.module_path[..] else { return false };
if seg1.ident.name != kw::Super {
return false;
}
let Some(def_id1) = glob_decl.res().opt_def_id() else { return false };
let Some(def_id2) = old_glob_decl.res().opt_def_id() else { return false };
self.def_path_str(def_id1).ends_with("tables::gsubgpos::Class")
&& self.def_path_str(def_id2).ends_with("ggg::Class")
}

fn is_pdf_0_9_0(&self, old_glob_decl: Decl<'ra>, glob_decl: Decl<'ra>) -> bool {
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Could this hack be removed since pdf-0.9.1 had fixed this (#149195 (comment))?

let DeclKind::Import { import: i1, .. } = glob_decl.kind else { unreachable!() };
let DeclKind::Import { import: i2, .. } = old_glob_decl.kind else { unreachable!() };
let [seg1, seg2] = &i1.module_path[..] else { return false };
if seg1.ident.name != kw::Crate || seg2.ident.name.as_str() != "content" {
return false;
}
let [seg1, seg2] = &i2.module_path[..] else { return false };
if seg1.ident.name != kw::Crate || seg2.ident.name.as_str() != "object" {
return false;
}
let Some(def_id1) = glob_decl.res().opt_def_id() else { return false };
let Some(def_id2) = old_glob_decl.res().opt_def_id() else { return false };
self.def_path_str(def_id1).ends_with("crate::content::Rect")
&& self.def_path_str(def_id2).ends_with("crate::object::types::Rect")
}

/// If `glob_decl` attempts to overwrite `old_glob_decl` in a module,
/// decide which one to keep.
fn select_glob_decl(
&self,
old_glob_decl: Decl<'ra>,
glob_decl: Decl<'ra>,
warn_ambiguity: bool,
) -> Decl<'ra> {
fn select_glob_decl(&self, old_glob_decl: Decl<'ra>, glob_decl: Decl<'ra>) -> Decl<'ra> {
assert!(glob_decl.is_glob_import());
assert!(old_glob_decl.is_glob_import());
assert_ne!(glob_decl, old_glob_decl);
Expand All @@ -476,9 +519,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
// all these overwrites will be re-fetched by glob imports importing
// from that module without generating new ambiguities.
// - A glob decl is overwritten by a non-glob decl arriving later.
// - A glob decl is overwritten by its clone after setting ambiguity in it.
// FIXME: avoid this by removing `warn_ambiguity`, or by triggering glob re-fetch
// with the same decl in some way.
// - A glob decl is overwritten by a glob decl re-fetching an
// overwritten decl from other module (the recursive case).
// Here we are detecting all such re-fetches and overwrite old decls
Expand All @@ -489,29 +529,20 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
if deep_decl != glob_decl {
// Some import layers have been removed, need to overwrite.
assert_ne!(old_deep_decl, old_glob_decl);
// FIXME: reenable the asserts when `warn_ambiguity` is removed (#149195).
// assert_ne!(old_deep_decl, deep_decl);
// assert!(old_deep_decl.is_glob_import());
assert!(!deep_decl.is_glob_import());
if old_glob_decl.ambiguity.get().is_some() && glob_decl.ambiguity.get().is_none() {
if let Some((old_ambig, _)) = old_glob_decl.ambiguity.get()
&& glob_decl.ambiguity.get().is_none()
{
// Do not lose glob ambiguities when re-fetching the glob.
glob_decl.ambiguity.set_unchecked(old_glob_decl.ambiguity.get());
}
if glob_decl.is_ambiguity_recursive() {
glob_decl.warn_ambiguity.set_unchecked(true);
glob_decl.ambiguity.set_unchecked(Some((old_ambig, true)));
}
glob_decl
} else if glob_decl.res() != old_glob_decl.res() {
old_glob_decl.ambiguity.set_unchecked(Some(glob_decl));
old_glob_decl.warn_ambiguity.set_unchecked(warn_ambiguity);
if warn_ambiguity {
old_glob_decl
} else {
// Need a fresh decl so other glob imports importing it could re-fetch it
// and set their own `warn_ambiguity` to true.
// FIXME: remove this when `warn_ambiguity` is removed (#149195).
self.arenas.alloc_decl((*old_glob_decl).clone())
}
let warning = self.is_noise_0_7_0(old_glob_decl, glob_decl)
|| self.is_rustybuzz_0_4_0(old_glob_decl, glob_decl)
|| self.is_pdf_0_9_0(old_glob_decl, glob_decl);
old_glob_decl.ambiguity.set_unchecked(Some((glob_decl, warning)));
old_glob_decl
} else if let old_vis = old_glob_decl.vis()
&& let vis = glob_decl.vis()
&& old_vis != vis
Expand All @@ -529,8 +560,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
old_glob_decl
} else if glob_decl.is_ambiguity_recursive() && !old_glob_decl.is_ambiguity_recursive() {
// Overwriting a non-ambiguous glob import with an ambiguous glob import.
old_glob_decl.ambiguity.set_unchecked(Some(glob_decl));
old_glob_decl.warn_ambiguity.set_unchecked(true);
old_glob_decl.ambiguity.set_unchecked(Some((glob_decl, true)));
old_glob_decl
} else {
old_glob_decl
Expand All @@ -545,9 +575,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
orig_ident_span: Span,
ns: Namespace,
decl: Decl<'ra>,
warn_ambiguity: bool,
) -> Result<(), Decl<'ra>> {
assert!(!decl.warn_ambiguity.get());
assert!(decl.ambiguity.get().is_none());
assert!(decl.ambiguity_vis_max.get().is_none());
assert!(decl.ambiguity_vis_min.get().is_none());
Expand All @@ -562,31 +590,21 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
module.underscore_disambiguator.update_unchecked(|d| d + 1);
module.underscore_disambiguator.get()
});
self.update_local_resolution(
module,
key,
orig_ident_span,
warn_ambiguity,
|this, resolution| {
if decl.is_glob_import() {
resolution.glob_decl = Some(match resolution.glob_decl {
Some(old_decl) => this.select_glob_decl(
old_decl,
decl,
warn_ambiguity && resolution.non_glob_decl.is_none(),
),
None => decl,
})
} else {
resolution.non_glob_decl = Some(match resolution.non_glob_decl {
Some(old_decl) => return Err(old_decl),
None => decl,
})
}
self.update_local_resolution(module, key, orig_ident_span, |this, resolution| {
if decl.is_glob_import() {
resolution.glob_decl = Some(match resolution.glob_decl {
Some(old_decl) => this.select_glob_decl(old_decl, decl),
None => decl,
});
} else {
resolution.non_glob_decl = Some(match resolution.non_glob_decl {
Some(old_decl) => return Err(old_decl),
None => decl,
})
}

Ok(())
},
)
Ok(())
})
}

// Use `f` to mutate the resolution of the name in the module.
Expand All @@ -596,15 +614,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
module: LocalModule<'ra>,
key: BindingKey,
orig_ident_span: Span,
warn_ambiguity: bool,
f: F,
) -> T
where
F: FnOnce(&Resolver<'ra, 'tcx>, &mut NameResolution<'ra>) -> T,
{
// Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
// during which the resolution might end up getting re-defined via a glob cycle.
let (binding, t, warn_ambiguity) = {
let (binding, t) = {
let resolution = &mut *self
.resolution_or_default(module.to_module(), key, orig_ident_span)
.borrow_mut_unchecked();
Expand All @@ -616,7 +633,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
if let Some(binding) = resolution.determined_decl()
&& (old_decl != Some(binding) || old_vis != Some(binding.vis()))
{
(binding, t, warn_ambiguity || old_decl.is_some())
(binding, t)
} else {
return t;
}
Expand All @@ -639,14 +656,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
};
if self.is_accessible_from(binding.vis(), scope) {
let import_decl = self.new_import_decl(binding, *import);
self.try_plant_decl_into_local_module(
ident,
orig_ident_span,
key.ns,
import_decl,
warn_ambiguity,
)
.expect("planting a glob cannot fail");
self.try_plant_decl_into_local_module(ident, orig_ident_span, key.ns, import_decl)
.expect("planting a glob cannot fail");
}
}

Expand All @@ -665,21 +676,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
self.per_ns(|this, ns| {
let ident = IdentKey::new(target);
// This can fail, dummies are inserted only in non-occupied slots.
let _ = this.try_plant_decl_into_local_module(
ident,
target.span,
ns,
dummy_decl,
false,
);
let _ = this.try_plant_decl_into_local_module(ident, target.span, ns, dummy_decl);
// Don't remove underscores from `single_imports`, they were never added.
if target.name != kw::Underscore {
let key = BindingKey::new(ident, ns);
this.update_local_resolution(
import.parent_scope.module.expect_local(),
key,
target.span,
false,
|_, resolution| {
resolution.single_imports.swap_remove(&import);
},
Expand Down Expand Up @@ -846,7 +850,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
}

if let DeclKind::Import { import, .. } = binding.kind
&& let Some(amb_binding) = binding.ambiguity.get()
&& let Some((amb_binding, _)) = binding.ambiguity.get()
&& binding.res() != Res::Err
&& exported_ambiguities.contains(&binding)
{
Expand Down Expand Up @@ -1134,7 +1138,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
parent.expect_local(),
key,
target.span,
false,
|_, resolution| {
resolution.single_imports.swap_remove(&import);
},
Expand Down Expand Up @@ -1820,16 +1823,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
};
if self.is_accessible_from(binding.vis(), scope) {
let import_decl = self.new_import_decl(binding, import);
let warn_ambiguity = self
.resolution(import.parent_scope.module, key)
.and_then(|r| r.determined_decl())
.is_some_and(|binding| binding.warn_ambiguity_recursive());
self.try_plant_decl_into_local_module(
key.ident,
orig_ident_span,
key.ns,
import_decl,
warn_ambiguity,
)
.expect("planting a glob cannot fail");
}
Expand Down
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