Valid, but rejected by DMD:

void function() a = {writeln("a");}, b = body {writeln("b");};

Valid, but rejected by DMD:

void function() a {writeln("a");}

Invalid, accepted by DMD:

void function() a = {writeln("a");};

Invalid, accepted by DMD:

// No semicolon needed if there's only one
void function() a = {writeln("a");}

For fun, accepted by DMD:

void function() bar[](alias t)(int x, int y) = { writeln("wat"); };

On Tuesday, 15 April 2014 at 18:11:13 UTC, Brian Schott wrote:
> Invalid, accepted by DMD:
>
> // No semicolon needed if there's only one
> void function() a = {writeln("a");}

Sorry, disregard this one.

In its place, let's use this, which is valid and rejected by DMD:

void function() bar {}

Decl:
    StorageClasses(opt) BasicType Declarator FunctionBody