gccrs: rust-unreachable: Add specific behavior for rust_unreachable

As discussed during the community call, rust_unreachable() should
always trigger an internal compiler error and should not offer
the behavior of __builtin_unreachable when asserts are disabled, unlike
gcc_unreachable().

gcc/rust/ChangeLog:

	* rust-system.h (rust_unreachable): Change definition to fancy_abort
	* ast/rust-ast-collector.cc (TokenCollector::visit): Use rust_unreachable
	instead of gcc_unreachable.
	(get_delimiters): Likewise.
	* ast/rust-ast-dump.h: Likewise.
	* ast/rust-ast-formatting.cc (get_string_in_delims): Likewise.
	(get_mode_dump_desc): Likewise.
	* ast/rust-ast.cc (Visibility::as_string): Likewise.
	(UseTreeGlob::as_string): Likewise.
	* ast/rust-ast.h: Likewise.
	* ast/rust-macro.h: Likewise.
	* ast/rust-path.h: Likewise.
	* backend/rust-compile-expr.cc (sort_tuple_patterns): Likewise.
	(CompileExpr::visit): Likewise.
	(CompileExpr::generate_closure_fntype): Likewise.
	* backend/rust-compile-intrinsic.cc (op_with_overflow_inner): Likewise.
	* backend/rust-compile-pattern.cc (CompilePatternBindings::visit): Likewise.
	(CompilePatternLet::visit): Likewise.
	* backend/rust-constexpr.cc (base_field_constructor_elt): Likewise.
	(eval_array_reference): Likewise.
	(label_matches): Likewise.
	(eval_store_expression): Likewise.
	(eval_call_expression): Likewise.
	(build_data_member_initialization): Likewise.
	(array_index_cmp): Likewise.
	(get_array_or_vector_nelts): Likewise.
	(eval_bit_field_ref): Likewise.
	(eval_loop_expr): Likewise.
	(potential_constant_expression_1): Likewise.
	* backend/rust-mangle.cc (v0_simple_type_prefix): Likewise.
	(v0_type_prefix): Likewise.
	(v0_mangle_item): Likewise.
	(Mangler::mangle_item): Likewise.
	* backend/rust-tree.cc (convert_to_void): Likewise.
	(type_memfn_quals): Likewise.
	(rs_tree_equal): Likewise.
	(fold_offsetof): Likewise.
	(fold_builtin_source_location): Likewise.
	(lvalue_error): Likewise.
	* backend/rust-tree.h (struct named_decl_hash): Likewise.
	(struct named_label_hash): Likewise.
	* checks/errors/privacy/rust-visibility-resolver.cc
	(VisibilityResolver::resolve_visibility): Likewise.
	(VisibilityResolver::visit): Likewise.
	* checks/errors/rust-const-checker.cc (ConstChecker::ctx_to_str): Likewise.
	* checks/errors/rust-feature.cc (Feature::create): Likewise.
	* expand/rust-expand-visitor.cc (get_traits_to_derive): Likewise.
	(derive_item): Likewise.
	(expand_item_attribute): Likewise.
	(expand_stmt_attribute): Likewise.
	* expand/rust-macro-expand.cc (MacroExpander::match_matcher): Likewise.
	(MacroExpander::match_repetition): Likewise.
	(transcribe_context): Likewise.
	(MacroExpander::import_proc_macros): Likewise.
	(MacroExpander::parse_proc_macro_output): Likewise.
	* expand/rust-macro-expand.h: Likewise.
	* expand/rust-macro-invoc-lexer.h: Likewise.
	* expand/rust-macro-substitute-ctx.cc (SubstituteCtx::substitute_token): Likewise.
	* expand/rust-proc-macro-invoc-lexer.h: Likewise.
	* expand/rust-proc-macro.cc (load_macros): Likewise.
	* hir/rust-ast-lower-base.cc (ASTLoweringBase::lower_generic_args): Likewise.
	(ASTLoweringBase::lower_literal): Likewise.
	* hir/rust-ast-lower-expr.cc (ASTLoweringExpr::visit): Likewise.
	* hir/rust-ast-lower-pattern.cc (ASTLoweringPattern::visit): Likewise.
	* hir/rust-ast-lower-type.cc (ASTLoweringType::visit): Likewise.
	* hir/rust-hir-dump.cc (Dump::visit): Likewise.
	* hir/tree/rust-hir.cc (get_string_in_delims): Likewise.
	(Visibility::as_string): Likewise.
	(UseTreeGlob::as_string): Likewise.
	(CompoundAssignmentExpr::as_string): Likewise.
	(ArithmeticOrLogicalExpr::as_string): Likewise.
	* lex/rust-lex.cc (Lexer::parse_byte_string): Likewise.
	(Lexer::parse_string): Likewise.
	* lex/rust-token.cc (RS_TOKEN): Likewise.
	* parse/rust-parse-impl.h (Parser::parse_simple_path_segment): Likewise.
	(Parser::parse_path_ident_segment): Likewise.
	(Parser::parse_attr_input): Likewise.
	(Parser::parse_inherent_impl_item): Likewise.
	(Parser::parse_trait_impl_item): Likewise.
	(Parser::parse_type_path_segment): Likewise.
	(Parser::parse_reference_type): Likewise.
	(get_lbp_for_comparison_expr): Likewise.
	* parse/rust-parse.cc (peculiar_fragment_match_compatible): Likewise.
	* resolve/rust-ast-resolve-path.cc (ResolvePath::resolve_path): Likewise.
	* resolve/rust-ast-resolve-pattern.cc (PatternDeclaration::visit): Likewise.
	* resolve/rust-ast-resolve-type.cc (ResolveRelativeTypePath::go): Likewise.
	(ResolveTypeToCanonicalPath::visit): Likewise.
	(ResolveGenericArgs::resolve_disambiguated_generic): Likewise.
	* rust-gcc.cc (operator_to_tree_code): Likewise.
	(fetch_overflow_builtins): Likewise.
	(Gcc_backend::non_zero_size_type): Likewise.
	(Gcc_backend::convert_tree): Likewise.
	* rust-lang.cc (grs_langhook_type_for_mode): Likewise.
	(grs_langhook_global_bindings_p): Likewise.
	(grs_langhook_pushdecl): Likewise.
	(grs_langhook_getdecls): Likewise.
	(convert): Likewise.
	* typecheck/rust-autoderef.h: Likewise.
	* typecheck/rust-hir-path-probe.cc: Likewise.
	* typecheck/rust-hir-trait-reference.cc (TraitItemReference::get_tyty): Likewise.
	* typecheck/rust-hir-type-check-base.cc (TypeCheckBase::resolve_literal): Likewise.
	* typecheck/rust-hir-type-check-expr.cc: Likewise.
	* typecheck/rust-hir-type-check-expr.h: Likewise.
	* typecheck/rust-hir-type-check-implitem.cc (TypeCheckImplItem::visit): Likewise.
	* typecheck/rust-hir-type-check-pattern.cc (TypeCheckPattern::visit): Likewise.
	* typecheck/rust-hir-type-check-stmt.h: Likewise.
	* typecheck/rust-hir-type-check.cc (TraitItemReference::get_type_from_fn): Likewise.
	* typecheck/rust-substitution-mapper.h: Likewise.
	* typecheck/rust-typecheck-context.cc (TypeCheckContextItem::get_context_type): Likewise.
	* typecheck/rust-tyty-call.h: Likewise.
	* typecheck/rust-tyty.cc (TypeKindFormat::to_string): Likewise.
	(BaseType::monomorphized_clone): Likewise.
	(VariantDef::variant_type_string): Likewise.
	(ClosureType::handle_substitions): Likewise.
	(IntType::as_string): Likewise.
	(UintType::as_string): Likewise.
	(FloatType::as_string): Likewise.
	* typecheck/rust-unify.cc (UnifyRules::expect_projection): Likewise.
	* util/rust-token-converter.cc (convert): Likewise.
	(from_literal): Likewise.
	(from_group): Likewise.
	(from_tokentree): Likewise.

1 files changed, 2 insertions, 2 deletions

diff --git a/gcc/rust/ast/rust-macro.h b/gcc/rust/ast/rust-macro.h
index 1620ff6..55fbd3a 100644
--- a/gcc/rust/ast/rust-macro.h
+++ b/gcc/rust/ast/rust-macro.h
@@ -473,14 +473,14 @@ private:
 
   /**
    * Default function to use as an associated transcriber. This function should
-   * never be called, hence the gcc_unreachable().
+   * never be called, hence the rust_unreachable().
    * If this function is used, then the macro is not builtin and the compiler
    * should make use of the actual rules. If the macro is builtin, then another
    * associated transcriber should be used
    */
   static Fragment dummy_builtin (Location, MacroInvocData &)
   {
-    gcc_unreachable ();
+    rust_unreachable ();
     return Fragment::create_error ();
   }