I have this piece of code and I can't understand why the `static if` conditionals are always false.

```
import std.digest.sha;
import std.file;
import std.stdio;

void main()
{
    auto hash1 = produceHash!string("prova.d");
    auto hash2 = produceHash!File(File("./prova.d"));
}

string produceHash(Type)(Type data)
    if(is(Type == string) || is(Type == File))
{
    string h;
    static if(is(Type == File)) {
        enforce(data.exists, "File does not exist.");
        // Hashing both name and file, to avoid having the same Hash on empty files
        return toHexString(digest!SHA256(data.byChunk(4096*1024))).dup;
    } else static if(is(Type == string)){
        return toHexString(digest!SHA256(data)).dup;
    }
    static assert(false, "Data must be string or file. ");
}
```

```
prova.d(22): Error: static assert  "Data must be string or file. "
prova.d(7):        instantiated from here: produceHash!string
```

On Thursday, 26 April 2018 at 15:06:49 UTC, sungal wrote:
> I have this piece of code and I can't understand why the `static if` conditionals are always false.
>
> ```
> import std.digest.sha;
> import std.file;
> import std.stdio;
>
> void main()
> {
>     auto hash1 = produceHash!string("prova.d");
>     auto hash2 = produceHash!File(File("./prova.d"));
> }
>
> string produceHash(Type)(Type data)
>     if(is(Type == string) || is(Type == File))
> {
>     string h;
>     static if(is(Type == File)) {
>         enforce(data.exists, "File does not exist.");
>         // Hashing both name and file, to avoid having the same Hash on empty files
>         return toHexString(digest!SHA256(data.byChunk(4096*1024))).dup;
>     } else static if(is(Type == string)){
>         return toHexString(digest!SHA256(data)).dup;
>     }
>     static assert(false, "Data must be string or file. ");
> }
> ```
>
> ```
> prova.d(22): Error: static assert  "Data must be string or file. "
> prova.d(7):        instantiated from here: produceHash!string
> ```

The static assert is unconditionally evaluated after the static if/else clause. This leads to a compile time assertion failure.
Add an "else", maybe.