http://d.puremagic.com/issues/show_bug.cgi?id=8995
Summary: `is(<Type> <Identifier> == function)` creates tuple
with parameter storage classes
Product: D
Version: D2
Platform: All
OS/Version: All
Status: NEW
Severity: normal
Priority: P2
Component: DMD
AssignedTo: [email protected]
ReportedBy: [email protected]
--- Comment #0 from Denis Shelomovskij <[email protected]> 2012-11-11
10:28:55 MSK ---
Function parameter types tuple retrieved with `IsExpression` contains parameter
storage classes unless indexed (slicing remains storage classes).
It is not documented that typetuple can contain parameter storage classes so it
may lead to unexpected behavior and looks inconsistent because `is(typetuple1
== typetuple2)` is `true` for tuples with different storage classes.
---
template TypeTuple(T...)
{ alias T TypeTuple; }
template t(alias func)
{
static if (is(typeof(func) Args == function))
{
static assert(is(Args == TypeTuple!(int, int, int, int))); // passes
pragma(msg, "Args: ", Args); // (int, ref int, out int, auto int)
pragma(msg, "Args[1..2]: ", Args[1..2]); // (ref int)
pragma(msg, "Args[1]: ", Args[1]); // int
void g1(Args[0 .. 3]) { } // void(int, ref int, out int)
pragma(msg, "typeof(g1): ", typeof(g1));
void g2(Args[3]) { } // void(int)
pragma(msg, "typeof(g2): ", typeof(g2));
void g3(Args[3 .. 4]) { } // void(auto ref int), error, line 20
}
else
static assert(0);
}
void f(T)(int, ref int, out int, auto ref T)
{
alias t!f tf;
}
void main()
{
int i;
f(0, i, i, 0);
}
---
Compiler output:
---
Args: (int, ref int, out int, auto int)
Args[1..2]: (ref int)
Args[1]: int
typeof(g1): void(int, ref int, out int)
typeof(g2): void(int)
main.d(20): Error: auto can only be used for template function parameters
main.d(29): Error: template instance main.t!(f) error instantiating
main.d(36): instantiated from here: f!(int)
main.d(36): Error: template instance main.f!(int) error instantiating
---
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