ci: exclude coverage of isbits functions

src/Expression.jl

@@ -506,12 +506,14 @@ end
 # We don't require users to overload this, as it's not part of the required interface.
 # Also, there's no way to generally do this from the required interface, so for backwards
 # compatibility, we just return nothing.
+# COV_EXCL_START
 function copy_into!(::Nothing, src::AbstractExpression)
     return copy(src)
 end
 function allocate_container(::AbstractExpression, ::Union{Nothing,Integer}=nothing)
     return nothing
 end
+# COV_EXCL_STOP
 function allocate_container(prototype::Expression, n::Union{Nothing,Integer}=nothing)
     return (; tree=allocate_container(get_contents(prototype), n))
 end

src/NodePreallocation.jl

@@ -48,10 +48,12 @@ function copy_into!(
         N,
     )
 end
+# COV_EXCL_START
 function leaf_copy_into!(dest::N, src::N) where {N<:AbstractExpressionNode}
     set_node!(dest, src)
     return dest
 end
+# COV_EXCL_STOP
 function branch_copy_into!(
     dest::N, src::N, children::Vararg{N,M}
 ) where {N<:AbstractExpressionNode,M}
@@ -64,5 +66,4 @@ function branch_copy_into!(
     return dest
 end
 
-
 end