diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/transform/check_consts/check.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/transform/check_consts/ops.rs | 10 |
2 files changed, 13 insertions, 1 deletions
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs index 54213d55a2d..fd166e3c938 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs @@ -730,6 +730,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { substs, span: *fn_span, from_hir_call: *from_hir_call, + feature: Some(sym::const_trait_impl), }); return; } @@ -802,6 +803,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { substs, span: *fn_span, from_hir_call: *from_hir_call, + feature: None, }); return; } @@ -844,6 +846,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { substs, span: *fn_span, from_hir_call: *from_hir_call, + feature: None, }); return; } @@ -903,6 +906,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { substs, span: *fn_span, from_hir_call: *from_hir_call, + feature: None, }); return; } diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs index b19d270e610..0cb5d2ff8c7 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs @@ -111,6 +111,7 @@ pub struct FnCallNonConst<'tcx> { pub substs: SubstsRef<'tcx>, pub span: Span, pub from_hir_call: bool, + pub feature: Option<Symbol>, } impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> { @@ -119,7 +120,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> { ccx: &ConstCx<'_, 'tcx>, _: Span, ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { - let FnCallNonConst { caller, callee, substs, span, from_hir_call } = *self; + let FnCallNonConst { caller, callee, substs, span, from_hir_call, feature } = *self; let ConstCx { tcx, param_env, .. } = *ccx; let diag_trait = |err, self_ty: Ty<'_>, trait_id| { @@ -318,6 +319,13 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> { ccx.const_kind(), )); + if let Some(feature) = feature && ccx.tcx.sess.is_nightly_build() { + err.help(&format!( + "add `#![feature({})]` to the crate attributes to enable", + feature, + )); + } + if let ConstContext::Static(_) = ccx.const_kind() { err.note("consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell"); } |