calling a macro function next to an unrelated genericBuild class

[Munir Hussin]

Hello. I'm refactoring my codes and changing stuff from hardcoded Foo1<T0>, Foo2<T0,T1> ... into Foo<Rest> using genericBuild to automatically create those FooN classes as needed.

However, I ran into a strange error, and I'm unsure if it's due to a mistake in my macro builder or if its a bug.

Here's a simplified version of the code to show the error:

Foo.hx:

package;

import haxe.macro.Context;

import haxe.macro.Expr;

import haxe.macro.Type;

using haxe.macro.TypeTools;

using haxe.macro.ComplexTypeTools;

@:genericBuild(FooMacro.build())

class Foo<Rest>

{

    public function new() trace("foo!");

}

class FooMacro

{

    public static var cache = new Map<Int, Bool>();

    

    public static macro function build():ComplexType

    {

        return switch(Context.getLocalType())

        {

            case TInst(_.get() => { name: "Foo" }, params):

                buildClass(params);

                

            case t:

                throw 'Incompatible type: $t';

        }

    }

    

    public static function buildClass(params:Array<Type>):ComplexType

    {

        var pos = Context.currentPos();

        var n = params.length;

        var className = 'Foo$n';

        

        if (!cache.exists(n))

        {

            var fields = Context.getBuildFields();

            

            Context.defineType(

            {

                pack: [],

                name: className,

                pos: pos,

                params: [for (i in 0...n) { name: 'T$i' }],

                kind: TDClass(),

                fields: fields

            });

            

            cache[n] = true;

        }

        

        return TPath({pack: [], name: className, params: [for (t in params) TPType(t.toComplexType())]});

    }

}

Main.hx

class Main

{

    

    public static function main()

    {

        var a = new Foo<Int, Int>();  // comment this, uncomment below: works

        bar();                        // comment this, uncomment above: works
                                      // both lines uncomment: error

    }

    
    // Calling this macro function results in an error
    // at the line with `new Foo<Int, Int>()`
    //    Unknown<0> cannot be constructed
    // The bar macro function has nothing to do with Foo

    public static macro function bar()

    {

        return macro null;

    }

}

Anyone knows how can I fix this? Thanks in advance.

[Ben Merckx]

Mixing genericBuild classes and macros in the same context can mess things up. I believe the next haxe release has a proper compile time error for this. The easiest way to fix this is to move the bar method to a seperate class. If you wish to keep it there you'll have to mark every usage of Foo (the import statement as well) in #if !macro ... #end

[Munir Hussin]

Both your suggestions worked. I didn't need to mark out the import statement of Foo, it somehow works too. Thanks! Much appreciated.