simplify macro does not permit templating?

I assume that's what's wrong with this

julia> using QuasiArrays, ContinuumArrays

julia> import ContinuumArrays: @simplify

julia> struct MyOp{T,Ax} <: QuasiArrays.LazyQuasiMatrix{T}
           axis::Ax
       end

julia> @simplify function *(A::MyOp, P::Basis{T}) where T
           P * Diagonal(1:∞)
       end
ERROR: LoadError: AssertionError: (qt.args[1]).head == :call
Stacktrace:
 [1] var"@simplify"(__source__::LineNumberNode, __module__::Module, qt::Any)
   @ ContinuumArrays ~/.julia/packages/ContinuumArrays/tg4mj/src/operators.jl:21
in expression starting at REPL[5]:1

Maybe it's not an issue because macros work with types?

Reproduce the Julia example and inspect the @simplify implementation at src/operators.jl:21, especially the assertion reported in the stack trace. Determine whether the macro is intended to accept the type-parameterized method shown; done means establishing the expected behavior and either correcting it or documenting the limitation.