crash with shifts inside array length

Nobody has claimed this yet.

auto-reduced (treereduce-rust):

//@compile-flags: -frust-incomplete-and-experimental-compiler-do-not-use
static FOO2: () = {
    let x = [47; (1 << 47) - 1];
};

original:

//@ only-64bit
// on 32bit and 16bit platforms it is plausible that the maximum allocation size will succeed
// FIXME (#135952) In some cases on AArch64 Linux the diagnostic does not trigger
//@ ignore-aix
// AIX will allow the allocation to go through, and get SIGKILL when zero initializing
// on 32bit and 16bit platforms it is plausible that the maximum allocation size will succeed
//@ ignore-aix

const FOO: () = {
    let x = [0_u8; (1 << 47) - 1];
    //~^ ERROR tried to allocate more memory than available to compiler
};

static FOO2: () = {
    let x = [47; (1 << 47) - 1];
    //~^ ERROR tried to allocate more memory than available to compiler
};

fn main() {
    let x = [0_u8; (1 << 47) - 1];
    //~^ ERROR tried to allocate more memory than available to compiler
}

Version information:

5dc8c4d20d62462ebce137c6e5146235ab9e9e2e

Command:
/home/matthias/vcs/github/gccrs/gccrs-build/gcc/crab1 -frust-incomplete-and-experimental-compiler-do-not-use

Program output

terminate called after throwing an instance of 'std::bad_alloc'
  what():  std::bad_alloc
crab1: internal compiler error: Aborted
0x2fecaf8 internal_error(char const*, ...)
	../../gcc/diagnostic-global-context.cc:517
0x196d57f crash_signal
	../../gcc/toplev.cc:321
0x11650a6 std::__new_allocator<unsigned long>::allocate(unsigned long, void const*)
	/usr/include/c++/15.1.1/bits/new_allocator.h:151
0x11650a6 std::allocator_traits<std::allocator<unsigned long> >::allocate(std::allocator<unsigned long>&, unsigned long)
	/usr/include/c++/15.1.1/bits/alloc_traits.h:614
0x11650a6 std::_Vector_base<unsigned long, std::allocator<unsigned long> >::_M_allocate(unsigned long)
	/usr/include/c++/15.1.1/bits/stl_vector.h:387
0x11650a6 std::vector<unsigned long, std::allocator<unsigned long> >::reserve(unsigned long)
	/usr/include/c++/15.1.1/bits/vector.tcc:79
0x11650a6 Rust::Compile::CompileExpr::array_copied_expr(unsigned long, Rust::TyTy::ArrayType const&, tree_node*, Rust::HIR::ArrayElemsCopied&)
	../../gcc/rust/backend/rust-compile-expr.cc:1997
0x116580b ???
	../../gcc/rust/backend/rust-compile-expr.h:42
0x1162c76 Rust::Compile::CompileExpr::Compile(Rust::HIR::Expr&, Rust::Compile::Context*)
	../../gcc/rust/backend/rust-compile-expr.cc:48
0x11599c6 Rust::Compile::CompileStmt::visit(Rust::HIR::LetStmt&)
	../../gcc/rust/backend/rust-compile-stmt.cc:71
0x1159b7c Rust::Compile::CompileStmt::Compile(Rust::HIR::Stmt*, Rust::Compile::Context*)
	../../gcc/rust/backend/rust-compile-stmt.cc:36
0x118a9fc Rust::Compile::HIRCompileBase::compile_function_body(tree_node*, Rust::HIR::BlockExpr&, Rust::TyTy::BaseType*)
	../../gcc/rust/backend/rust-compile-base.cc:613
0x118eb94 Rust::Compile::HIRCompileBase::compile_constant_item(unsigned int, Rust::TyTy::BaseType*, Rust::TyTy::BaseType*, Rust::Resolver::CanonicalPath const&, Rust::HIR::Expr&, unsigned long, unsigned long)
	../../gcc/rust/backend/rust-compile-base.cc:865
0x115782c Rust::Compile::CompileItem::visit(Rust::HIR::StaticItem&)
	../../gcc/rust/backend/rust-compile-item.cc:61
0xdbeeeb Rust::Compile::CompileItem::compile(Rust::HIR::Item*, Rust::Compile::Context*, Rust::TyTy::BaseType*, unsigned long)
	../../gcc/rust/backend/rust-compile-item.h:37
0xdbeeeb Rust::Compile::CompileCrate::go()
	../../gcc/rust/backend/rust-compile.cc:48
0xdbeeeb Rust::Compile::CompileCrate::Compile(Rust::HIR::Crate&, Rust::Compile::Context*)
	../../gcc/rust/backend/rust-compile.cc:41
0xdb9970 Rust::Session::compile_crate(char const*)
	../../gcc/rust/rust-session-manager.cc:732
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

Start with the reduced Rust case and the backtrace entry at gcc/rust/backend/rust-compile-expr.cc:1997, in array_copied_expr. Run crab1 with the reported compile flag and confirm the bad_alloc crash. Done means the large shifted array produces the expected allocation diagnostic instead of aborting the compiler.

Written by the indexing model from the issue text.

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