E3053

Error · Type

E3053 — An impl of Send or Sync with no unsafe, as in impl Send for Handle {}. The compiler derives both from the fields, and a raw pointer is neither. An impl claims one for a type that holds a raw pointer, and the compiler cannot check the claim. Write unsafe impl Send for Handle {}.

What the compiler reports

Error[E3053]: `impl Send for Handle` must be `unsafe impl`: the compiler derives `Send` from the fields, and cannot check this claim
Error[E3053]: `impl Sync for Handle` must be `unsafe impl`
Error[E3054]: `unsafe impl Describe for Handle`: only `Send` and `Sync` take `unsafe impl`. Remove `unsafe`
Error[E3054]: `unsafe impl Handle`: an impl with no trait cannot be `unsafe`
{{^}}Semantic check failed on {{.*}}: 4 error(s) emitted

The fragments the test suite holds the compiler to. An ellipsis marks text the test does not constrain; the emitted message also carries a source location.

A program that triggers it

//
// Part of the Vx Project, under the Apache License v2.0 with LLVM Exceptions.
// See LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// An impl of `Send` or `Sync` must be `unsafe impl` (E3053). Any other impl must not be (E3054).
//

import core::marker;

trait Describe {}

struct Handle {
  p : *mut i32,
}

impl Send for Handle {}

impl Sync for Handle {}

unsafe impl Describe for Handle {}

unsafe impl Handle {
  fn id(self : &Handle) -> i32 {
    return 1;
  }
}

fn main() -> i32 {
  return 0;
}

// The errors above are all the errors.

From tests/frontend/fail/unsafe_impl_only_for_send_and_sync.vx, which asserts this diagnostic on every commit.

A tour of VxThe chapter covering the rule this code enforces. All diagnosticsEvery code the compiler can emit, grouped by stage. E3052Arithmetic on fp8 or fp4 values (f8e4m3, f8e5m2 or f4e2m1) with no written result type, as in print(a * b). The compiler computes in f32 and rounds once to the written type, so the program must write it: let c : f32 = a * b;. Also += and the other compound operators on these values, and any operator on tensors of them. E3054unsafe impl of a trait other than Send or Sync, or of no trait at all. Only those two traits make a claim that the compiler cannot check. Remove unsafe.

E3053

What the compiler reports

A program that triggers it

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