| Issue |
134440
|
| Summary |
[clang-tidy] readability-redundant-member-init fails to account for explicit user-provided default constructors
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
connorsmacd-hh
|
The `readability-redundant-member-init` check issues warnings on initializers even when the relevant default constructor is **marked `explicit`** and is **user-provided**.
Example code ([godbolt here](https://godbolt.org/z/YPqKPvGz1)) with clang-tidy args `-checks=-*,readability-redundant-member-init`:
```C++
struct A
{
explicit A() {}
};
struct B
{
A a1 {}; // Compiles, but tidy detects a redundant member init
A a2; // No warning from tidy, but does not compile
};
auto b = B{};
```
In the above example, clang-tidy flags the `a1` line with:
```
<source>:8:10: warning: initializer for member 'a1' is redundant [readability-redundant-member-init]
8 | A a1 {}; // Compiles, but tidy detects a redundant member init
```
When I do what tidy wants in the `a2` line, this fails to compile with:
```
<source>:12:12: error: chosen constructor is explicit in copy-initialization
12 | auto b = B{};
| ^
<source>:3:14: note: explicit constructor declared here
3 | explicit A() {}
| ^
<source>:9:7: note: in implicit initialization of field 'a2' with omitted initializer
9 | A a2; // No warning from tidy, but does not compile
| ^
1 error generated.
Compiler returned: 1
```
Interestingly, clang-tidy no longer warns if the constructor is instead explicitly defaulted, i.e., `explicit A() = default;`.
For context, I encountered this issue when working with `boost::circular_buffer`'s default constructor ([docs here](https://www.boost.org/doc/libs/1_87_0/doc/html/doxygen/boost_circular_buffer_c___reference/classboost_1_1circular__buffer.html#doxygen.boost_circular_buffer_c___reference.classboost_1_1circular__buffer_1a00b4cb2a7dd9c100008c05ba18c43575)):
```C++
explicit circular_buffer(const allocator_type & alloc = allocator_type()) noexcept;
```
It seems to me that `readability-redundant-member-init` should ignore instances where the initializer is invoking an explicit default constructor. Is that correct or am I doing something wrong?
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
