Unrolled build for #141559

Rollup merge of #141559 - RalfJung:less-rustc_allow_const_fn_unstable, r=compiler-errors

const-check: stop recommending the use of rustc_allow_const_fn_unstable

I have seen way too many people see the compiler suggest this attribute and then just apply it without a second thought. This is bad. So let's just stop recommending it; for the rare case where someone needs it, they'll eventually ask us and that way we can be sure that it is truly needed. The dev-guide still also explains `rustc_allow_const_fn_unstable`.

Cc ``@rust-lang/wg-const-eval``

Author: rust-timer

compiler/rustc_const_eval/messages.ftl

@@ -424,8 +424,7 @@ const_eval_unstable_in_stable_exposed =
     .unstable_sugg = if the {$is_function_call2 ->
             [true] caller
             *[false] function
-        } is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
-    .bypass_sugg = otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
+        } is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
 
 const_eval_unstable_intrinsic = `{$name}` is not yet stable as a const intrinsic
 const_eval_unstable_intrinsic_suggestion = add `#![feature({$feature})]` to the crate attributes to enable

compiler/rustc_const_eval/src/errors.rs

@@ -58,11 +58,6 @@ pub(crate) struct UnstableInStableExposed {
         code = "#[rustc_const_unstable(feature = \"...\", issue = \"...\")]\n",
         applicability = "has-placeholders"
     )]
-    #[suggestion(
-        const_eval_bypass_sugg,
-        code = "#[rustc_allow_const_fn_unstable({gate})]\n",
-        applicability = "has-placeholders"
-    )]
     pub attr_span: Span,
 }
 

tests/ui/consts/const-eval/dont_promote_unstable_const_fn.stderr

@@ -5,14 +5,9 @@ LL | const fn bar() -> u32 { foo() }
    |                         ^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar() -> u32 { foo() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo)]
 LL | const fn bar() -> u32 { foo() }
    |
 

tests/ui/consts/const-unstable-intrinsic.stderr

@@ -46,14 +46,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |         size_of_val(&x);
    |         ^^^^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn const_main() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(local)]
 LL | const fn const_main() {
    |
 
@@ -63,14 +58,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |         min_align_of_val(&x);
    |         ^^^^^^^^^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn const_main() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(local)]
 LL | const fn const_main() {
    |
 
@@ -88,14 +78,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |         super::size_of_val(src);
    |         ^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL +     #[rustc_const_unstable(feature = "...", issue = "...")]
-LL |     const unsafe fn copy<T>(src: *const T, _dst: *mut T, _count: usize) {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL +     #[rustc_allow_const_fn_unstable(local)]
 LL |     const unsafe fn copy<T>(src: *const T, _dst: *mut T, _count: usize) {
    |
 

tests/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr

@@ -5,14 +5,9 @@ LL | const fn bar() -> u32 { foo() }
    |                         ^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar() -> u32 { foo() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo)]
 LL | const fn bar() -> u32 { foo() }
    |
 
@@ -23,14 +18,9 @@ LL | const fn bar2() -> u32 { foo2() }
    |                          ^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar2() -> u32 { foo2() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const fn bar2() -> u32 { foo2() }
    |
 
@@ -40,14 +30,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     let x = async { 13 };
    |             ^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar3() -> u32 {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(const_async_blocks)]
 LL | const fn bar3() -> u32 {
    |
 
@@ -58,14 +43,9 @@ LL |     foo()
    |     ^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar3() -> u32 {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo)]
 LL | const fn bar3() -> u32 {
    |
 
@@ -76,14 +56,9 @@ LL | const fn bar2_gated() -> u32 { foo2_gated() }
    |                                ^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn bar2_gated() -> u32 { foo2_gated() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const fn bar2_gated() -> u32 { foo2_gated() }
    |
 
@@ -94,14 +69,9 @@ LL |     pub(crate) const fn bar2_gated_stable_indirect() -> u32 { super::foo2_g
    |                                                               ^^^^^^^^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL +     #[rustc_const_unstable(feature = "...", issue = "...")]
-LL |     pub(crate) const fn bar2_gated_stable_indirect() -> u32 { super::foo2_gated() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL +     #[rustc_allow_const_fn_unstable(foo2)]
 LL |     pub(crate) const fn bar2_gated_stable_indirect() -> u32 { super::foo2_gated() }
    |
 
@@ -112,14 +82,9 @@ LL | const fn stable_indirect() -> u32 { foo2_gated() }
    |                                     ^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn stable_indirect() -> u32 { foo2_gated() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const fn stable_indirect() -> u32 { foo2_gated() }
    |
 

tests/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr

@@ -5,14 +5,9 @@ LL | const unsafe fn bar() -> u32 { unsafe { foo() } }
    |                                         ^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar() -> u32 { unsafe { foo() } }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo)]
 LL | const unsafe fn bar() -> u32 { unsafe { foo() } }
    |
 
@@ -23,14 +18,9 @@ LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } }
    |                                          ^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } }
    |
 
@@ -41,14 +31,9 @@ LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } }
    |                                                ^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } }
    |
 

tests/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr

@@ -5,14 +5,9 @@ LL | const unsafe fn bar() -> u32 { foo() }
    |                                ^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar() -> u32 { foo() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo)]
 LL | const unsafe fn bar() -> u32 { foo() }
    |
 
@@ -23,14 +18,9 @@ LL | const unsafe fn bar2() -> u32 { foo2() }
    |                                 ^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar2() -> u32 { foo2() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const unsafe fn bar2() -> u32 { foo2() }
    |
 
@@ -41,14 +31,9 @@ LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() }
    |                                       ^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() }
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(foo2)]
 LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() }
    |
 

tests/ui/consts/min_const_fn/recursive_const_stab_unmarked_crate_imports.stderr

@@ -5,14 +5,9 @@ LL |     unstable_if_unmarked_const_fn_crate::not_stably_const();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | const fn stable_fn() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(rustc_private)]
 LL | const fn stable_fn() {
    |
 

tests/ui/consts/min_const_fn/recursive_const_stab_unstable_if_unmarked.stderr

@@ -5,14 +5,9 @@ LL |     not_stably_const();
    |     ^^^^^^^^^^^^^^^^^^
    |
    = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
-help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the caller is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | pub const fn expose_on_stable() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(rustc_private)]
 LL | pub const fn expose_on_stable() {
    |
 
@@ -22,14 +17,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     let _x = async { 15 };
    |              ^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | pub const fn expose_on_stable() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(const_async_blocks)]
 LL | pub const fn expose_on_stable() {
    |
 

tests/ui/intrinsics/const-eval-select-stability.stderr

@@ -4,14 +4,9 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     const_eval_select((), nothing, log);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
+help: if the function is not (yet) meant to be exposed to stable const contexts, add `#[rustc_const_unstable]`
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
-LL | pub const fn hey() {
-   |
-help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval)
-   |
-LL + #[rustc_allow_const_fn_unstable(const_eval_select)]
 LL | pub const fn hey() {
    |