From ebf024bba84242e0c4176583b80ddd1cba071c42 Mon Sep 17 00:00:00 2001 From: Dylan MacKenzie Date: Thu, 24 Sep 2020 11:11:53 -0700 Subject: [PATCH 1/2] Suggest `const_fn_transmute` instead of `const_fn` --- compiler/rustc_mir/src/transform/check_consts/ops.rs | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/compiler/rustc_mir/src/transform/check_consts/ops.rs b/compiler/rustc_mir/src/transform/check_consts/ops.rs index e14dcf92b89d2..9871300027740 100644 --- a/compiler/rustc_mir/src/transform/check_consts/ops.rs +++ b/compiler/rustc_mir/src/transform/check_consts/ops.rs @@ -489,7 +489,14 @@ impl NonConstOp for Transmute { } fn emit_error(&self, ccx: &ConstCx<'_, '_>, span: Span) { - mcf_emit_error(ccx, span, "can only call `transmute` from const items, not `const fn`"); + feature_err( + &ccx.tcx.sess.parse_sess, + sym::const_fn_transmute, + span, + &format!("`transmute` is not allowed in {}s", ccx.const_kind()), + ) + .note("`transmute` is only allowed in constants and statics for now") + .emit(); } } From 0f594698aaa2b8330eca219f38105d2f4989c977 Mon Sep 17 00:00:00 2001 From: Dylan MacKenzie Date: Thu, 24 Sep 2020 11:12:28 -0700 Subject: [PATCH 2/2] Bless tests --- .../feature-gate-const_fn_transmute.rs | 18 ++--- .../feature-gate-const_fn_transmute.stderr | 65 +++++++++++-------- .../ui/internal/internal-unstable-const.rs | 2 +- .../internal/internal-unstable-const.stderr | 9 +-- 4 files changed, 52 insertions(+), 42 deletions(-) diff --git a/src/test/ui/feature-gates/feature-gate-const_fn_transmute.rs b/src/test/ui/feature-gates/feature-gate-const_fn_transmute.rs index 981680b5d1fad..9007e501bc2bf 100644 --- a/src/test/ui/feature-gates/feature-gate-const_fn_transmute.rs +++ b/src/test/ui/feature-gates/feature-gate-const_fn_transmute.rs @@ -6,33 +6,33 @@ struct Foo(u32); const TRANSMUTED_U32: u32 = unsafe { mem::transmute(Foo(3)) }; const fn transmute_fn() -> u32 { unsafe { mem::transmute(Foo(3)) } } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const fn transmute_fn_intrinsic() -> u32 { unsafe { std::intrinsics::transmute(Foo(3)) } } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const fn transmute_fn_core_intrinsic() -> u32 { unsafe { core::intrinsics::transmute(Foo(3)) } } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const unsafe fn unsafe_transmute_fn() -> u32 { mem::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const unsafe fn unsafe_transmute_fn_intrinsic() -> u32 { std::intrinsics::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const unsafe fn unsafe_transmute_fn_core_intrinsic() -> u32 { core::intrinsics::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` const fn safe_transmute_fn() -> u32 { mem::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` //~| ERROR call to unsafe function is unsafe and requires unsafe function or block const fn safe_transmute_fn_intrinsic() -> u32 { std::intrinsics::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` //~| ERROR call to unsafe function is unsafe and requires unsafe function or block const fn safe_transmute_fn_core_intrinsic() -> u32 { core::intrinsics::transmute(Foo(3)) } -//~^ ERROR can only call `transmute` from const items, not `const fn` +//~^ ERROR `transmute` //~| ERROR call to unsafe function is unsafe and requires unsafe function or block fn main() {} diff --git a/src/test/ui/feature-gates/feature-gate-const_fn_transmute.stderr b/src/test/ui/feature-gates/feature-gate-const_fn_transmute.stderr index 44430fd577d88..08ba14dc40e86 100644 --- a/src/test/ui/feature-gates/feature-gate-const_fn_transmute.stderr +++ b/src/test/ui/feature-gates/feature-gate-const_fn_transmute.stderr @@ -1,83 +1,92 @@ -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:8:43 | LL | const fn transmute_fn() -> u32 { unsafe { mem::transmute(Foo(3)) } } | ^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:11:53 | LL | const fn transmute_fn_intrinsic() -> u32 { unsafe { std::intrinsics::transmute(Foo(3)) } } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:14:58 | LL | const fn transmute_fn_core_intrinsic() -> u32 { unsafe { core::intrinsics::transmute(Foo(3)) } } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:17:48 | LL | const unsafe fn unsafe_transmute_fn() -> u32 { mem::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:20:58 | LL | const unsafe fn unsafe_transmute_fn_intrinsic() -> u32 { std::intrinsics::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:23:63 | LL | const unsafe fn unsafe_transmute_fn_core_intrinsic() -> u32 { core::intrinsics::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:26:39 | LL | const fn safe_transmute_fn() -> u32 { mem::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:30:49 | LL | const fn safe_transmute_fn_intrinsic() -> u32 { std::intrinsics::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/feature-gate-const_fn_transmute.rs:34:54 | LL | const fn safe_transmute_fn_core_intrinsic() -> u32 { core::intrinsics::transmute(Foo(3)) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now error[E0133]: call to unsafe function is unsafe and requires unsafe function or block --> $DIR/feature-gate-const_fn_transmute.rs:26:39 @@ -105,5 +114,5 @@ LL | const fn safe_transmute_fn_core_intrinsic() -> u32 { core::intrinsics::tran error: aborting due to 12 previous errors -Some errors have detailed explanations: E0133, E0723. +Some errors have detailed explanations: E0133, E0658. For more information about an error, try `rustc --explain E0133`. diff --git a/src/test/ui/internal/internal-unstable-const.rs b/src/test/ui/internal/internal-unstable-const.rs index b923bc22f6e5f..554c67be4e0b0 100644 --- a/src/test/ui/internal/internal-unstable-const.rs +++ b/src/test/ui/internal/internal-unstable-const.rs @@ -8,7 +8,7 @@ #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "rust1", since = "1.0.0")] pub const fn foo() -> i32 { - unsafe { std::mem::transmute(4u32) } //~ ERROR can only call `transmute` from const items + unsafe { std::mem::transmute(4u32) } //~ ERROR `transmute` } fn main() {} diff --git a/src/test/ui/internal/internal-unstable-const.stderr b/src/test/ui/internal/internal-unstable-const.stderr index 9626df23ec3c2..adfb8dc36918d 100644 --- a/src/test/ui/internal/internal-unstable-const.stderr +++ b/src/test/ui/internal/internal-unstable-const.stderr @@ -1,12 +1,13 @@ -error[E0723]: can only call `transmute` from const items, not `const fn` +error[E0658]: `transmute` is not allowed in constant functions --> $DIR/internal-unstable-const.rs:11:14 | LL | unsafe { std::mem::transmute(4u32) } | ^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #53605 for more information + = help: add `#![feature(const_fn_transmute)]` to the crate attributes to enable + = note: `transmute` is only allowed in constants and statics for now error: aborting due to previous error -For more information about this error, try `rustc --explain E0723`. +For more information about this error, try `rustc --explain E0658`.