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Enum member std.traits.ifTestable

enum ifTestable(T, alias pred) = __traits(compiles, () { if (pred(T.init)) { } } );


true iff the type T can be tested in an if-expression, that is if if (pred(T.init)) {} is compilable.


class C;
struct S1;
struct S2
    T opCast(T)() const;

static assert( ifTestable!bool);
static assert( ifTestable!int);
static assert( ifTestable!(S1*));
static assert( ifTestable!(typeof(null)));
static assert( ifTestable!(int[]));
static assert( ifTestable!(int[string]));
static assert( ifTestable!S2);
static assert( ifTestable!C);
static assert(!ifTestable!S1);


Walter Bright, Tomasz Stachowiak (isExpressions), Andrei Alexandrescu, Shin Fujishiro, Robert Clipsham, David Nadlinger, Kenji Hara, Shoichi Kato


Boost License 1.0.