fix hasmethod with kwargs to exclude positional arg names (#58410)

(cherry picked from commit 7df60f4)

Author: JeffBezanson

base/reflection.jl

@@ -1851,11 +1851,11 @@ function hasmethod(f, t, kwnames::Tuple{Vararg{Symbol}}; world::UInt=get_world_c
     match = ccall(:jl_gf_invoke_lookup, Any, (Any, Any, UInt), tt, nothing, world)
     match === nothing && return false
     kws = ccall(:jl_uncompress_argnames, Array{Symbol,1}, (Any,), (match::Method).slot_syms)
+    kws = kws[((match::Method).nargs + 1):end] # remove positional arguments
     isempty(kws) && return true # some kwfuncs simply forward everything directly
     for kw in kws
         endswith(String(kw), "...") && return true
     end
-    kwnames = Symbol[kwnames[i] for i in 1:length(kwnames)]
     return issubset(kwnames, kws)
 end
 

test/reflection.jl

@@ -825,6 +825,7 @@ f(x::Int; y=3) = x + y
 @test hasmethod(f, Tuple{Int})
 @test hasmethod(f, Tuple{Int}, ())
 @test hasmethod(f, Tuple{Int}, (:y,))
+@test !hasmethod(f, Tuple{Int}, (:x,))
 @test !hasmethod(f, Tuple{Int}, (:jeff,))
 @test !hasmethod(f, Tuple{Int}, (:y,), world=typemin(UInt))
 g(; b, c, a) = a + b + c