Remove no longer used contract_checks intrinsic

The contract_checks compiler flag is now used to determine
if runtime contract checks should be enabled, as opposed
to the compiler intrinsic as previously.

Author: dawidl022

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -115,7 +115,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 | sym::assert_mem_uninitialized_valid
                 | sym::assert_inhabited
                 | sym::ub_checks
-                | sym::contract_checks
                 | sym::atomic_fence
                 | sym::atomic_singlethreadfence
                 | sym::caller_location => {}

compiler/rustc_feature/src/builtin_attrs.rs

@@ -22,7 +22,6 @@ const GATED_CFGS: &[GatedCfg] = &[
     // (name in cfg, feature, function to check if the feature is enabled)
     (sym::overflow_checks, sym::cfg_overflow_checks, Features::cfg_overflow_checks),
     (sym::ub_checks, sym::cfg_ub_checks, Features::cfg_ub_checks),
-    (sym::contract_checks, sym::cfg_contract_checks, Features::cfg_contract_checks),
     (sym::target_thread_local, sym::cfg_target_thread_local, Features::cfg_target_thread_local),
     (
         sym::target_has_atomic_equal_alignment,

compiler/rustc_hir/src/lang_items.rs

@@ -429,7 +429,6 @@ language_item_table! {
     // Experimental lang items for implementing contract pre- and post-condition checking.
     ContractBuildCheckEnsures, sym::contract_build_check_ensures, contract_build_check_ensures_fn, Target::Fn, GenericRequirement::None;
     ContractCheckRequires,     sym::contract_check_requires,      contract_check_requires_fn,      Target::Fn, GenericRequirement::None;
-    ContractChecks,            sym::contract_checks,              contract_checks_fn,              Target::Fn, GenericRequirement::None;
 
     // Experimental lang items for `MCP: Low level components for async drop`(https://github.com/rust-lang/compiler-team/issues/727)
     DefaultTrait4,           sym::default_trait4,      default_trait4_trait,       Target::Trait,          GenericRequirement::None;

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -123,7 +123,6 @@ fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: LocalDefId) -> hi
         | sym::aggregate_raw_ptr
         | sym::ptr_metadata
         | sym::ub_checks
-        | sym::contract_checks
         | sym::contract_check_requires
         | sym::contract_check_ensures
         | sym::fadd_algebraic
@@ -568,8 +567,6 @@ pub(crate) fn check_intrinsic_type(
 
         sym::box_new => (1, 0, vec![param(0)], Ty::new_box(tcx, param(0))),
 
-        // contract_checks() -> bool
-        sym::contract_checks => (0, 0, Vec::new(), tcx.types.bool),
         // contract_check_requires::<C>(C) -> bool, where C: impl Fn() -> bool
         sym::contract_check_requires => (1, 0, vec![param(0)], tcx.types.unit),
         sym::contract_check_ensures => {

compiler/rustc_mir_transform/src/lower_intrinsics.rs

@@ -34,17 +34,6 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                         ));
                         terminator.kind = TerminatorKind::Goto { target };
                     }
-                    sym::contract_checks => {
-                        let target = target.unwrap();
-                        block.statements.push(Statement::new(
-                            terminator.source_info,
-                            StatementKind::Assign(Box::new((
-                                *destination,
-                                Rvalue::NullaryOp(NullOp::ContractChecks, tcx.types.bool),
-                            ))),
-                        ));
-                        terminator.kind = TerminatorKind::Goto { target };
-                    }
                     sym::forget => {
                         let target = target.unwrap();
                         block.statements.push(Statement::new(

compiler/rustc_session/src/config/cfg.rs

@@ -118,7 +118,6 @@ pub(crate) fn disallow_cfgs(sess: &Session, user_cfgs: &Cfg) {
             (sym::overflow_checks, None) => disallow(cfg, "-C overflow-checks"),
             (sym::debug_assertions, None) => disallow(cfg, "-C debug-assertions"),
             (sym::ub_checks, None) => disallow(cfg, "-Z ub-checks"),
-            (sym::contract_checks, None) => disallow(cfg, "-Z contract-checks"),
             (sym::sanitize, None | Some(_)) => disallow(cfg, "-Z sanitizer"),
             (
                 sym::sanitizer_cfi_generalize_pointers | sym::sanitizer_cfi_normalize_integers,
@@ -305,10 +304,6 @@ pub(crate) fn default_configuration(sess: &Session) -> Cfg {
         ins_none!(sym::emscripten_wasm_eh);
     }
 
-    if sess.contract_checks() {
-        ins_none!(sym::contract_checks);
-    }
-
     ret
 }
 
@@ -469,7 +464,6 @@ impl CheckCfg {
         ins!(sym::target_thread_local, no_values);
 
         ins!(sym::ub_checks, no_values);
-        ins!(sym::contract_checks, no_values);
 
         ins!(sym::unix, no_values);
         ins!(sym::windows, no_values);

compiler/rustc_span/src/symbol.rs

@@ -747,7 +747,6 @@ symbols! {
         contract_build_check_ensures,
         contract_check_ensures,
         contract_check_requires,
-        contract_checks,
         contracts,
         contracts_ensures,
         contracts_internals,

library/core/src/intrinsics/mod.rs

@@ -2576,24 +2576,6 @@ pub const unsafe fn const_make_global(ptr: *mut u8) -> *const u8 {
     ptr
 }
 
-/// Returns whether we should perform contract-checking at runtime.
-///
-/// This is meant to be similar to the ub_checks intrinsic, in terms
-/// of not prematurely committing at compile-time to whether contract
-/// checking is turned on, so that we can specify contracts in libstd
-/// and let an end user opt into turning them on.
-#[unstable(feature = "contracts_internals", issue = "128044" /* compiler-team#759 */)]
-#[rustc_const_unstable(feature = "contracts", issue = "128044")]
-#[inline(always)]
-#[lang = "contract_checks"]
-#[rustc_intrinsic]
-pub const fn contract_checks() -> bool {
-    // FIXME: should this be `false` or `cfg!(contract_checks)`?
-
-    // cfg!(contract_checks)
-    false
-}
-
 /// Check if the pre-condition `cond` has been met.
 ///
 /// By default, if `contract_checks` is enabled, this will panic with no unwind if the condition

tests/ui/contracts/internal_machinery/contract-intrinsics.rs

@@ -1,36 +1,23 @@
-//@ revisions: default unchk_pass chk_pass chk_fail_ensures chk_fail_requires
+//@ revisions: default chk_fail_ensures chk_fail_requires
 //
 //@ [default] run-pass
-//@ [unchk_pass] run-pass
-//@ [chk_pass] run-pass
 //@ [chk_fail_requires] run-crash
 //@ [chk_fail_ensures] run-crash
-//
-//@ [unchk_pass] compile-flags: -Zcontract-checks=no
-//@ [chk_pass] compile-flags: -Zcontract-checks=yes
-//@ [chk_fail_requires] compile-flags: -Zcontract-checks=yes
-//@ [chk_fail_ensures] compile-flags: -Zcontract-checks=yes
 #![feature(cfg_contract_checks, contracts_internals, core_intrinsics)]
 
 fn main() {
-    #[cfg(any(default, unchk_pass))] // default: disabled
-    assert_eq!(core::intrinsics::contract_checks(), false);
-
-    #[cfg(chk_pass)] // explicitly enabled
-    assert_eq!(core::intrinsics::contract_checks(), true);
-
     // always pass
     core::intrinsics::contract_check_requires(|| true);
 
     // always fail
-    #[cfg(any(chk_fail_requires))]
+    #[cfg(chk_fail_requires)]
     core::intrinsics::contract_check_requires(|| false);
 
     let doubles_to_two = { let old = 2; move |ret: &u32 | ret + ret == old };
     // Always pass
     core::intrinsics::contract_check_ensures(Some(doubles_to_two), 1);
 
     // always fail
-    #[cfg(any(chk_fail_ensures))]
+    #[cfg(chk_fail_ensures)]
     core::intrinsics::contract_check_ensures(Some(doubles_to_two), 2);
 }

tests/ui/contracts/internal_machinery/contract-lang-items.chk_fail_post.stderr

@@ -1,5 +1,5 @@
 warning: the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/contract-lang-items.rs:15:12
+  --> $DIR/contract-lang-items.rs:8:12
    |
 LL | #![feature(contracts)] // to access core::contracts
    |            ^^^^^^^^^