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check_attr: cover multi-segment attributes on specific check arms
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PR #128581 introduced an assertion that all builtin attributes are
actually checked via `CheckAttrVisitor` and aren't accidentally usable
on completely unrelated HIR nodes. Unfortunately, the check had
correctness problems.

The match on attribute path segments looked like

```rust,ignore
[sym::should_panic] => /* check is implemented */
match BUILTIN_ATTRIBUTE_MAP.get(name) {
    // checked below
    Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
    Some(_) => {
        if !name.as_str().starts_with("rustc_") {
            span_bug!(
                attr.span,
                "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
            )
        }
    }
    None => (),
}
```

However, it failed to account for edge cases such as an attribute whose:

1. path segments *starts* with a builtin attribute such as
   `should_panic`
2. which does not start with `rustc_`, and
3. is also an `AttributeType::Normal` attribute upon registration with
   the builtin attribute map

These conditions when all satisfied cause the span bug to be issued for e.g.
`#[should_panic::skip]` because the `[sym::should_panic]` arm is not matched (since it's
`[sym::should_panic, sym::skip]`).

See <#128622>.
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@jieyouxu
jieyouxu committed Aug 4, 2024
1 parent 9e5c9c1 commit 9d0eaa2
Showing 1 changed file with 73 additions and 71 deletions.
144 changes: 73 additions & 71 deletions compiler/rustc_passes/src/check_attr.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,130 +116,130 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
let attrs = self.tcx.hir().attrs(hir_id);
for attr in attrs {
match attr.path().as_slice() {
[sym::diagnostic, sym::do_not_recommend] => {
[sym::diagnostic, sym::do_not_recommend, ..] => {
self.check_do_not_recommend(attr.span, hir_id, target)
}
[sym::diagnostic, sym::on_unimplemented] => {
[sym::diagnostic, sym::on_unimplemented, ..] => {
self.check_diagnostic_on_unimplemented(attr.span, hir_id, target)
}
[sym::inline] => self.check_inline(hir_id, attr, span, target),
[sym::coverage] => self.check_coverage(attr, span, target),
[sym::optimize] => self.check_optimize(hir_id, attr, target),
[sym::non_exhaustive] => self.check_non_exhaustive(hir_id, attr, span, target),
[sym::marker] => self.check_marker(hir_id, attr, span, target),
[sym::target_feature] => {
[sym::inline, ..] => self.check_inline(hir_id, attr, span, target),
[sym::coverage, ..] => self.check_coverage(attr, span, target),
[sym::optimize, ..] => self.check_optimize(hir_id, attr, target),
[sym::non_exhaustive, ..] => self.check_non_exhaustive(hir_id, attr, span, target),
[sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
[sym::target_feature, ..] => {
self.check_target_feature(hir_id, attr, span, target, attrs)
}
[sym::thread_local] => self.check_thread_local(attr, span, target),
[sym::track_caller] => {
[sym::thread_local, ..] => self.check_thread_local(attr, span, target),
[sym::track_caller, ..] => {
self.check_track_caller(hir_id, attr.span, attrs, span, target)
}
[sym::doc] => self.check_doc_attrs(
[sym::doc, ..] => self.check_doc_attrs(
attr,
hir_id,
target,
&mut specified_inline,
&mut doc_aliases,
),
[sym::no_link] => self.check_no_link(hir_id, attr, span, target),
[sym::export_name] => self.check_export_name(hir_id, attr, span, target),
[sym::rustc_layout_scalar_valid_range_start]
| [sym::rustc_layout_scalar_valid_range_end] => {
[sym::no_link, ..] => self.check_no_link(hir_id, attr, span, target),
[sym::export_name, ..] => self.check_export_name(hir_id, attr, span, target),
[sym::rustc_layout_scalar_valid_range_start, ..]
| [sym::rustc_layout_scalar_valid_range_end, ..] => {
self.check_rustc_layout_scalar_valid_range(attr, span, target)
}
[sym::allow_internal_unstable] => {
[sym::allow_internal_unstable, ..] => {
self.check_allow_internal_unstable(hir_id, attr, span, target, attrs)
}
[sym::debugger_visualizer] => self.check_debugger_visualizer(attr, target),
[sym::rustc_allow_const_fn_unstable] => {
[sym::debugger_visualizer, ..] => self.check_debugger_visualizer(attr, target),
[sym::rustc_allow_const_fn_unstable, ..] => {
self.check_rustc_allow_const_fn_unstable(hir_id, attr, span, target)
}
[sym::rustc_std_internal_symbol] => {
[sym::rustc_std_internal_symbol, ..] => {
self.check_rustc_std_internal_symbol(attr, span, target)
}
[sym::naked] => self.check_naked(hir_id, attr, span, target, attrs),
[sym::rustc_never_returns_null_ptr] => {
[sym::naked, ..] => self.check_naked(hir_id, attr, span, target, attrs),
[sym::rustc_never_returns_null_ptr, ..] => {
self.check_applied_to_fn_or_method(hir_id, attr, span, target)
}
[sym::rustc_legacy_const_generics] => {
[sym::rustc_legacy_const_generics, ..] => {
self.check_rustc_legacy_const_generics(hir_id, attr, span, target, item)
}
[sym::rustc_lint_query_instability] => {
[sym::rustc_lint_query_instability, ..] => {
self.check_rustc_lint_query_instability(hir_id, attr, span, target)
}
[sym::rustc_lint_diagnostics] => {
[sym::rustc_lint_diagnostics, ..] => {
self.check_rustc_lint_diagnostics(hir_id, attr, span, target)
}
[sym::rustc_lint_opt_ty] => self.check_rustc_lint_opt_ty(attr, span, target),
[sym::rustc_lint_opt_deny_field_access] => {
[sym::rustc_lint_opt_ty, ..] => self.check_rustc_lint_opt_ty(attr, span, target),
[sym::rustc_lint_opt_deny_field_access, ..] => {
self.check_rustc_lint_opt_deny_field_access(attr, span, target)
}
[sym::rustc_clean]
| [sym::rustc_dirty]
| [sym::rustc_if_this_changed]
| [sym::rustc_then_this_would_need] => self.check_rustc_dirty_clean(attr),
[sym::rustc_coinductive]
| [sym::rustc_must_implement_one_of]
| [sym::rustc_deny_explicit_impl]
| [sym::const_trait] => self.check_must_be_applied_to_trait(attr, span, target),
[sym::cmse_nonsecure_entry] => {
[sym::rustc_clean, ..]
| [sym::rustc_dirty, ..]
| [sym::rustc_if_this_changed, ..]
| [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
[sym::rustc_coinductive, ..]
| [sym::rustc_must_implement_one_of, ..]
| [sym::rustc_deny_explicit_impl, ..]
| [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr, span, target),
[sym::cmse_nonsecure_entry, ..] => {
self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
}
[sym::collapse_debuginfo] => self.check_collapse_debuginfo(attr, span, target),
[sym::must_not_suspend] => self.check_must_not_suspend(attr, span, target),
[sym::must_use] => self.check_must_use(hir_id, attr, target),
[sym::rustc_pass_by_value] => self.check_pass_by_value(attr, span, target),
[sym::rustc_allow_incoherent_impl] => {
[sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
[sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
[sym::must_use, ..] => self.check_must_use(hir_id, attr, target),
[sym::rustc_pass_by_value, ..] => self.check_pass_by_value(attr, span, target),
[sym::rustc_allow_incoherent_impl, ..] => {
self.check_allow_incoherent_impl(attr, span, target)
}
[sym::rustc_has_incoherent_inherent_impls] => {
[sym::rustc_has_incoherent_inherent_impls, ..] => {
self.check_has_incoherent_inherent_impls(attr, span, target)
}
[sym::ffi_pure] => self.check_ffi_pure(attr.span, attrs, target),
[sym::ffi_const] => self.check_ffi_const(attr.span, target),
[sym::rustc_const_unstable]
| [sym::rustc_const_stable]
| [sym::unstable]
| [sym::stable]
| [sym::rustc_allowed_through_unstable_modules]
| [sym::rustc_promotable] => self.check_stability_promotable(attr, target),
[sym::link_ordinal] => self.check_link_ordinal(attr, span, target),
[sym::rustc_confusables] => self.check_confusables(attr, target),
[sym::rustc_safe_intrinsic] => {
[sym::ffi_pure, ..] => self.check_ffi_pure(attr.span, attrs, target),
[sym::ffi_const, ..] => self.check_ffi_const(attr.span, target),
[sym::rustc_const_unstable, ..]
| [sym::rustc_const_stable, ..]
| [sym::unstable, ..]
| [sym::stable, ..]
| [sym::rustc_allowed_through_unstable_modules, ..]
| [sym::rustc_promotable, ..] => self.check_stability_promotable(attr, target),
[sym::link_ordinal, ..] => self.check_link_ordinal(attr, span, target),
[sym::rustc_confusables, ..] => self.check_confusables(attr, target),
[sym::rustc_safe_intrinsic, ..] => {
self.check_rustc_safe_intrinsic(hir_id, attr, span, target)
}
[sym::cold] => self.check_cold(hir_id, attr, span, target),
[sym::link] => self.check_link(hir_id, attr, span, target),
[sym::link_name] => self.check_link_name(hir_id, attr, span, target),
[sym::link_section] => self.check_link_section(hir_id, attr, span, target),
[sym::no_mangle] => self.check_no_mangle(hir_id, attr, span, target),
[sym::deprecated] => self.check_deprecated(hir_id, attr, span, target),
[sym::macro_use] | [sym::macro_escape] => {
[sym::cold, ..] => self.check_cold(hir_id, attr, span, target),
[sym::link, ..] => self.check_link(hir_id, attr, span, target),
[sym::link_name, ..] => self.check_link_name(hir_id, attr, span, target),
[sym::link_section, ..] => self.check_link_section(hir_id, attr, span, target),
[sym::no_mangle, ..] => self.check_no_mangle(hir_id, attr, span, target),
[sym::deprecated, ..] => self.check_deprecated(hir_id, attr, span, target),
[sym::macro_use, ..] | [sym::macro_escape, ..] => {
self.check_macro_use(hir_id, attr, target)
}
[sym::path] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
[sym::macro_export] => self.check_macro_export(hir_id, attr, target),
[sym::ignore] | [sym::should_panic] => {
[sym::path, ..] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
[sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
[sym::ignore, ..] | [sym::should_panic, ..] => {
self.check_generic_attr(hir_id, attr, target, Target::Fn)
}
[sym::automatically_derived] => {
[sym::automatically_derived, ..] => {
self.check_generic_attr(hir_id, attr, target, Target::Impl)
}
[sym::no_implicit_prelude] => {
[sym::no_implicit_prelude, ..] => {
self.check_generic_attr(hir_id, attr, target, Target::Mod)
}
[sym::rustc_object_lifetime_default] => self.check_object_lifetime_default(hir_id),
[sym::proc_macro] => {
[sym::rustc_object_lifetime_default, ..] => self.check_object_lifetime_default(hir_id),
[sym::proc_macro, ..] => {
self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
}
[sym::proc_macro_attribute] => {
[sym::proc_macro_attribute, ..] => {
self.check_proc_macro(hir_id, target, ProcMacroKind::Attribute);
}
[sym::proc_macro_derive] => {
[sym::proc_macro_derive, ..] => {
self.check_generic_attr(hir_id, attr, target, Target::Fn);
self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
}
[sym::coroutine] => {
[sym::coroutine, ..] => {
self.check_coroutine(attr, target);
}
[
Expand Down Expand Up @@ -273,14 +273,16 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
| sym::default_lib_allocator
| sym::start
| sym::custom_mir,
..
] => {}
[name, ..] => {
match BUILTIN_ATTRIBUTE_MAP.get(name) {
// checked below
Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
Some(_) => {
// FIXME: differentiate between unstable and internal attributes just like we do with features instead
// of just accepting `rustc_` attributes by name. That should allow trimming the above list, too.
// FIXME: differentiate between unstable and internal attributes just
// like we do with features instead of just accepting `rustc_`
// attributes by name. That should allow trimming the above list, too.
if !name.as_str().starts_with("rustc_") {
span_bug!(
attr.span,
Expand Down

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