================
@@ -420,21 +420,52 @@ around, such as ``std::string_view``.
cplusplus.Move (C++)
""""""""""""""""""""
-Method calls on a moved-from object and copying a moved-from object will be
reported.
-
+Find use-after-move bugs in C++. This includes method calls on moved-from
+objects, assignment of a moved-from object, and repeated move of a moved-from
+object.
.. code-block:: cpp
- struct A {
+ struct A {
void foo() {}
};
- void f() {
+ void f1() {
A a;
A b = std::move(a); // note: 'a' became 'moved-from' here
a.foo(); // warn: method call on a 'moved-from' object 'a'
}
+ void f2() {
+ A a;
+ A b = std::move(a);
+ A c(std::move(a)); // warn: move of an already moved-from object
+ }
+
+ void f3() {
+ A a;
+ A b = std::move(a);
+ b = a; // warn: copy of moved-from object
+ }
+
+The checker option ``WarnOn`` controls on what objects the use-after-move is
+checked. The most strict value is ``KnownsOnly``, in this mode only objects are
+checked whose type is known to be move-unsafe. These include most STL objects
+(but excluding move-safe ones) and smart pointers. With option value
+``KnownsAndLocals`` local variables (of any type) are additionally checked. The
+idea behind this is that local variables are usually not tempting to be re-used
+so an use after move is more likely a bug than with member variables. With
+option value ``All`` any use-after move condition is checked on all kinds of
+variables, excluding global variables and known move-safe cases. Default value
+is ``KnownsAndLocals``.
----------------
NagyDonat wrote:
```suggestion
The checker option ``WarnOn`` controls on what objects the use-after-move is
checked.
* The most strict value is ``KnownsOnly``, in this mode only objects are
checked whose type is known to be move-unsafe. These include most STL objects
(but excluding move-safe ones) and smart pointers.
* With option value ``KnownsAndLocals`` local variables (of any type) are
additionally checked. The idea behind this is that local variables are
usually not tempting to be re-used so an use after move is more likely a bug
than with member variables.
* With option value ``All`` any use-after move condition is checked on all
kinds of variables, excluding global variables and known move-safe cases.
Default value is ``KnownsAndLocals``.
```
This paragraph was very long, re-flow it into a bullet point list.
https://github.com/llvm/llvm-project/pull/96295
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