StyleChecker
Underscore
Summary
Avoid including an underscore character (_) in the identifier of
local variables, local functions, and parameters.
Default severity
Warning
Description
Don't use underscores in identifies.
Discards
This analyzer ignores discards [1]. So it does not emit diagnostics to the following code:
// standalone: be ignored as long as no identifier named '_' is in scope.
_ = "hello".Length;
// tuple
(int, int) NewPoint(int x, int y) => (x, y);
var (one, _) = NewPoint(1, 2);
// out parameter
void Out(out int x) => x = 3;
Out(out _);
// pattern matching (is)
if ("hello" is string _)
{
...
}
// pattern matching (switch)
switch ("hello")
{
case string _:
break;
...
}
Lambda parameters
This analyzer also checks the input parameters of lambda expressions [2]. So it emits diagnostics to the following code:
Func<int, int, int> f = (a, _) => a;
Code fix
The code fix provides an option replacing the identifier with underscore
if the identifier contains only _ (a single underscore character). Otherwise,
it provides an option of eliminating underscores in the identifier and
concatenating words in the camel case style.
Example
Diagnostic
public void Method(int _param)
{
var _ = 0;
var max_retry_count = 100;
if (TryToGet(out var return_value))
{
}
if (this is object _o)
{
⋮
}
void Local_Function()
{
}
⋮
Code fix
public void Method(int param)
{
var underscore = 0;
var maxRetryCount = 100;
if (TryToGet(out var returnValue))
{
}
if (this is object o)
{
⋮
}
void LocalFunction()
{
}
⋮