"Linking two modules of different data layouts"

I'm getting this error when using fragmentLinkedFunctions in Metal.

Compiler failed to build request

exception: Error Domain=CompilerError Code=2 "

Linking two modules of different data layouts: '' is '' whereas '1' is 'e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:256:256-v256:256:256-v512:512:512-v1024:1024:1024-n8:16:32'

SC compilation failure

More boolean const than hw allows" UserInfo={NSLocalizedDescription=

Linking two modules of different data layouts: '' is '' whereas '1' is 'e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:256:256-v256:256:256-v512:512:512-v1024:1024:1024-n8:16:32'

SC compilation failure

More boolean const than hw allows}

Anyone know what that all means?

If I replace the body of my intersection function with just return {false, 0.0f}, I get only the More boolean const than hw allows.