segfault in Rust::AST::SingleASTNode::SingleASTNode / Type::clone_type()

original:

// Under the 2015 edition with the keyword_idents lint, `dyn` is
// not entirely acceptable as an identifier.
//
// We currently do not attempt to detect or fix uses of `dyn` as an
// identifier under a macro.
//
//@ check-pass
//@ edition:2015

#![allow(non_camel_case_types)]
#![deny(keyword_idents)]

mod outer_mod {
    pub mod r#dyn {
        pub struct r#dyn;
    }
}

// Here we are illustrating that the current lint does not flag the
// occurrences of `dyn` in this macro definition; however, it
// certainly *could* (and it would be nice if it did), since these
// occurrences are not compatible with the 2018 edition's
// interpretation of `dyn` as a keyword.
macro_rules! defn_has_dyn_idents {
    () => { ::outer_mod::dyn::dyn }
}

struct X;
trait Trait { fn defn_has_dyn_idents(&self) { }}
impl Trait for X { }

macro_rules! tt_trait {
    ($id:ident) => { & $arg tt_trait }
}

macro_rules! id_trait {
    ($id:ident) => { & $id Trait }
}

fn main() {
    defn_has_dyn_idents!();

    // Here we are illustrating that the current lint does not flag
    // the occurrences of `dyn` in these macro invocations. It
    // definitely should *not* flag the one in `tt_trait`, since that
    // is expanding in a valid fashion to `&dyn Trait`.
    //
    // It is arguable whether it would be valid to flag the occurrence
    // in `id_trait`, since that macro specifies that it takes an
    // `ident` as its input.
    fn f_tt(x: &X) -> tt_trait!(dyn) { x }
    fn f_id(x: &X) -> id_trait!(dyn) { x }

    let x = X;
    f_tt(&x).hello();
    f_id(&x).hello();
}

/tmp/icemaker_global_tempdir.ypCSWBUKJ5AY/rustc_testrunner_tmpdir_reporting.tSpefpM5HnNA/mvce.rs:8:24: error: failed to parse path as first component of type no bounds
    8 |     ($id:ident) => { & $arg tt_trait }
      |                        ^
/tmp/icemaker_global_tempdir.ypCSWBUKJ5AY/rustc_testrunner_tmpdir_reporting.tSpefpM5HnNA/mvce.rs:8:24: error: failed to parse referenced type in reference type
crab1: internal compiler error: Segmentation fault
0x2fecaf8 internal_error(char const*, ...)
	../../gcc/diagnostic-global-context.cc:517
0x196d57f crash_signal
	../../gcc/toplev.cc:321
0xcab3f4 Rust::AST::Type::clone_type() const
	../../gcc/rust/ast/rust-ast.h:1512
0xcab3f4 Rust::AST::SingleASTNode::SingleASTNode(Rust::AST::SingleASTNode const&)
	../../gcc/rust/ast/rust-ast.cc:71
0xddb181 void std::_Construct<Rust::AST::SingleASTNode, Rust::AST::SingleASTNode const&>(Rust::AST::SingleASTNode*, Rust::AST::SingleASTNode const&)
	/usr/include/c++/15.1.1/bits/stl_construct.h:133
0xddb181 Rust::AST::SingleASTNode* std::__do_uninit_copy<Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*>(Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*)
	/usr/include/c++/15.1.1/bits/stl_uninitialized.h:145
0xddb181 Rust::AST::SingleASTNode* std::uninitialized_copy<Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*>(Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*)
	/usr/include/c++/15.1.1/bits/stl_uninitialized.h:266
0xddb181 Rust::AST::SingleASTNode* std::__uninitialized_copy_a<Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*, Rust::AST::SingleASTNode>(Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode*, std::allocator<Rust::AST::SingleASTNode>&)
	/usr/include/c++/15.1.1/bits/stl_uninitialized.h:637
0xddb181 void std::vector<Rust::AST::SingleASTNode, std::allocator<Rust::AST::SingleASTNode> >::_M_range_initialize_n<Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*>(Rust::AST::SingleASTNode const*, Rust::AST::SingleASTNode const*, unsigned long)
	/usr/include/c++/15.1.1/bits/stl_vector.h:1988
0xddb181 std::vector<Rust::AST::SingleASTNode, std::allocator<Rust::AST::SingleASTNode> >::vector(std::initializer_list<Rust::AST::SingleASTNode>, std::allocator<Rust::AST::SingleASTNode> const&)
	/usr/include/c++/15.1.1/bits/stl_vector.h:712
0xddb181 transcribe_type
	../../gcc/rust/expand/rust-macro-expand.cc:978
0xddb181 transcribe_context
	../../gcc/rust/expand/rust-macro-expand.cc:1020
0xddb181 Rust::MacroExpander::transcribe_rule(Rust::AST::MacroRulesDefinition&, Rust::AST::MacroRule&, Rust::AST::DelimTokenTree&, std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, Rust::MatchedFragmentContainer*, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, Rust::MatchedFragmentContainer*> > >&, Rust::AST::InvocKind, Rust::MacroExpander::ContextType)
	../../gcc/rust/expand/rust-macro-expand.cc:1106
0xdde7f3 Rust::MacroExpander::expand_decl_macro(unsigned long, Rust::AST::MacroInvocData&, Rust::AST::MacroRulesDefinition&, Rust::AST::InvocKind)
	../../gcc/rust/expand/rust-macro-expand.cc:127
0xddedf5 Rust::MacroExpander::expand_invoc(Rust::AST::MacroInvocation&, Rust::AST::InvocKind)
	../../gcc/rust/expand/rust-macro-expand.cc:309
0xe9bb19 Rust::ExpandVisitor::maybe_expand_type(std::unique_ptr<Rust::AST::Type, std::default_delete<Rust::AST::Type> >&)
	../../gcc/rust/expand/rust-expand-visitor.cc:353
0xe9cc30 Rust::ExpandVisitor::visit(Rust::AST::Function&)
	../../gcc/rust/expand/rust-expand-visitor.cc:765
0xea10db void Rust::ExpandVisitor::expand_macro_children<std::vector<std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> >, std::allocator<std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> > > >, std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> > >(std::vector<std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> >, std::allocator<std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> > > >&, std::function<std::unique_ptr<Rust::AST::Stmt, std::default_delete<Rust::AST::Stmt> > (Rust::AST::SingleASTNode)>)
	../../gcc/rust/expand/rust-expand-visitor.h:131
0xea10db Rust::ExpandVisitor::expand_inner_stmts(Rust::AST::BlockExpr&)
	../../gcc/rust/expand/rust-expand-visitor.cc:330
0xea2290 Rust::ExpandVisitor::visit(Rust::AST::BlockExpr&)
	../../gcc/rust/expand/rust-expand-visitor.cc:630
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Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.