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// Copyright (C) 2020-2025 Free Software Foundation, Inc.
// This file is part of GCC.
// GCC is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3, or (at your option) any later
// version.
// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
// You should have received a copy of the GNU General Public License
// along with GCC; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
#include "rust-feature-gate.h"
#include "rust-abi.h"
#include "rust-attribute-values.h"
#include "rust-ast-visitor.h"
#include "rust-feature.h"
namespace Rust {
void
FeatureGate::check (AST::Crate &crate)
{
visit (crate);
}
void
FeatureGate::visit (AST::Crate &crate)
{
valid_features.clear ();
for (const auto &attr : crate.inner_attrs)
{
if (attr.get_path ().as_string () == "feature")
{
const auto &attr_input = attr.get_attr_input ();
auto type = attr_input.get_attr_input_type ();
if (type == AST::AttrInput::AttrInputType::TOKEN_TREE)
{
const auto &option = static_cast<const AST::DelimTokenTree &> (
attr.get_attr_input ());
std::unique_ptr<AST::AttrInputMetaItemContainer> meta_item (
option.parse_to_meta_item ());
for (const auto &item : meta_item->get_items ())
{
const auto &name_str = item->as_string ();
auto tname = Feature::as_name (name_str);
if (tname.has_value ())
{
auto name = tname.value ();
valid_features.insert (name);
}
else
rust_error_at (item->get_locus (), ErrorCode::E0635,
"unknown feature %qs", name_str.c_str ());
}
}
}
}
AST::DefaultASTVisitor::visit (crate);
}
void
FeatureGate::gate (Feature::Name name, location_t loc,
const std::string &error_msg)
{
if (!valid_features.count (name))
{
auto feature = Feature::create (name);
auto issue = feature.issue ();
if (issue > 0)
{
const char *fmt_str
= "%s. see issue %u "
"<https://github.com/rust-lang/rust/issues/%u> for more "
"information. add `#![feature(%s)]` to the crate attributes to "
"enable.";
rust_error_at (loc, ErrorCode::E0658, fmt_str, error_msg.c_str (),
issue, issue, feature.as_string ().c_str ());
}
else
{
const char *fmt_str
= "%s. add `#![feature(%s)]` to the crate attributes to enable.";
rust_error_at (loc, ErrorCode::E0658, fmt_str, error_msg.c_str (),
feature.as_string ().c_str ());
}
}
}
void
FeatureGate::visit (AST::ExternBlock &block)
{
if (block.has_abi ())
{
const auto abi = block.get_abi ();
if (get_abi_from_string (abi) == ABI::INTRINSIC)
gate (Feature::Name::INTRINSICS, block.get_locus (),
"intrinsics are subject to change");
}
AST::DefaultASTVisitor::visit (block);
}
void
FeatureGate::check_rustc_attri (const std::vector<AST::Attribute> &attributes)
{
for (const AST::Attribute &attr : attributes)
{
auto name = attr.get_path ().as_string ();
if (name.rfind ("rustc_", 0) == 0)
{
gate (Feature::Name::RUSTC_ATTRS, attr.get_locus (),
"internal implementation detail");
}
}
}
void
FeatureGate::check_may_dangle_attribute (
const std::vector<AST::Attribute> &attributes)
{
for (const AST::Attribute &attr : attributes)
{
if (attr.get_path ().as_string () == Values::Attributes::MAY_DANGLE)
gate (Feature::Name::DROPCK_EYEPATCH, attr.get_locus (),
"`may_dangle` has unstable semantics and may be removed in the "
"future");
}
}
void
FeatureGate::visit (AST::MacroRulesDefinition &rules_def)
{
check_rustc_attri (rules_def.get_outer_attrs ());
}
void
FeatureGate::visit (AST::Function &function)
{
if (!function.is_external ())
check_rustc_attri (function.get_outer_attrs ());
AST::DefaultASTVisitor::visit (function);
}
void
FeatureGate::visit (AST::ExternalTypeItem &item)
{
// TODO(mxlol233): The gating needs a complete visiting chain to activate
// `AST::ExternalTypeItem`.
gate (Feature::Name::EXTERN_TYPES, item.get_locus (),
"extern types are experimental");
}
void
FeatureGate::visit (AST::TraitImpl &impl)
{
if (impl.is_exclam ())
gate (Feature::Name::NEGATIVE_IMPLS, impl.get_locus (),
"negative_impls are not yet implemented");
AST::DefaultASTVisitor::visit (impl);
};
void
FeatureGate::visit (AST::BoxExpr &expr)
{
gate (
Feature::Name::BOX_SYNTAX, expr.get_locus (),
"box expression syntax is experimental; you can call `Box::new` instead");
AST::DefaultASTVisitor::visit (expr);
}
void
FeatureGate::visit (AST::LifetimeParam &lifetime_param)
{
check_may_dangle_attribute (lifetime_param.get_outer_attrs ());
AST::DefaultASTVisitor::visit (lifetime_param);
}
void
FeatureGate::visit (AST::ConstGenericParam &const_param)
{
check_may_dangle_attribute (const_param.get_outer_attrs ());
AST::DefaultASTVisitor::visit (const_param);
}
void
FeatureGate::visit (AST::TypeParam ¶m)
{
check_may_dangle_attribute (param.get_outer_attrs ());
AST::DefaultASTVisitor::visit (param);
}
void
FeatureGate::visit (AST::BorrowExpr &expr)
{
if (expr.is_raw_borrow ())
gate (Feature::Name::RAW_REF_OP, expr.get_locus (),
"raw address of syntax is experimental");
}
void
FeatureGate::visit (AST::RangePattern &pattern)
{
if (pattern.get_range_kind () == AST::RangeKind::EXCLUDED)
gate (Feature::Name::EXCLUSIVE_RANGE_PATTERN, pattern.get_locus (),
"exclusive range pattern syntax is experimental");
}
} // namespace Rust
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