[all-commits] [llvm/llvm-project] 1374aa: [clang] Don't infer lifetime_capture-by for refere...

[Haojian Wu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1374aa35a3f62c774548361276a87eb472893262
      https://github.com/llvm/llvm-project/commit/1374aa35a3f62c774548361276a87eb472893262
  Author: Haojian Wu <hokein.wu at gmail.com>
  Date:   2025-01-09 (Thu, 09 Jan 2025)

  Changed paths:
    M clang/lib/Sema/CheckExprLifetime.cpp
    M clang/lib/Sema/CheckExprLifetime.h
    M clang/lib/Sema/SemaAttr.cpp
    M clang/test/AST/attr-lifetime-capture-by.cpp
    M clang/test/Sema/warn-lifetime-analysis-capture-by.cpp

  Log Message:
  -----------
  [clang] Don't infer lifetime_capture-by for reference of raw pointer types. (#122240)

When a vector is instantiated with a pointer type (`T` being `const
Foo*`), the inferred annotation becomes `push_back(const Foo*& value
[[clang::lifetime_capture_by(this)]])`.

For reference parameters, the `lifetime_capture_by` attribute treats the
lifetime as referring to the referenced object -- in this case, the
**pointer** itself, not the pointee object. In the `push_back`, we copy
the pointer's value, which does not establish a reference to the
pointer. This behavior is safe and does not capture the pointer's
lifetime.

The annotation should not be inferred for cases where `T` is a pointer
type, as the intended semantics do not align with the annotation.

Fixes #121391



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