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const_item_mutation warning is triggered when modifying an array by pointer #79971

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#80133
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const_item_mutation warning is triggered when modifying an array by pointer#79971
#80133
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Aaron1011
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A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)A-lintsArea: Lints (warnings about flaws in source code) such as unused_mut.C-bugCategory: This is a bug.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

Description

@MSxDOS
MSxDOS
opened on Dec 12, 2020
const ARRAY: *mut [u32; 4] = 0x12345678 as _;

pub unsafe fn test(val: u32) {
    (*ARRAY)[0] = val;
}
Warning: attempting to modify a `const` item
 --> <source>:4:5
  |
4 |     (*ARRAY)[0] = val;
  |     ^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(const_item_mutation)]` on by default
  = note: each usage of a `const` item creates a new temporary; the original `const` item will not be modified
note: `const` item defined here
 --> <source>:1:1
  |
1 | const ARRAY: *mut [u32; 4] = 0x12345678 as _;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

#77324 missed that case.

Activity

  1. jonas-schievink
    added
    A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)
    A-lintsArea: Lints (warnings about flaws in source code) such as unused_mut.
    C-bugCategory: This is a bug.
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    on Dec 12, 2020
  2. Aaron1011
    self-assigned this
    on Dec 14, 2020
  3. Aaron1011
    added a commit that references this issue on Dec 17, 2020

    Suppress `CONST_ITEM_MUTATION` lint if a dereference occurs anywhere

    dea1363
  4. Dylan-DPC-zz
    added a commit that references this issue on Dec 19, 2020

    Rollup merge of rust-lang#80133 - Aaron1011:fix/const-mut-deref, r=es…

    66042fc
  5. JohnTitor
    added a commit that references this issue on Dec 19, 2020

    Rollup merge of rust-lang#80133 - Aaron1011:fix/const-mut-deref, r=es…

    6b52475
  6. bors
    closed this as completedin dea1363on Dec 19, 2020
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A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)A-lintsArea: Lints (warnings about flaws in source code) such as unused_mut.C-bugCategory: This is a bug.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

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