diff --git a/base/compiler/tfuncs.jl b/base/compiler/tfuncs.jl
index d4bc7253da23da..ec8dc92eec5138 100644
--- a/base/compiler/tfuncs.jl
+++ b/base/compiler/tfuncs.jl
@@ -1056,7 +1056,7 @@ function _builtin_nothrow(@nospecialize(f), argtypes::Array{Any,1}, @nospecializ
         length(argtypes) == 1 || return false
         return sizeof_nothrow(argtypes[1])
     elseif f === Core.kwfunc
-        length(argtypes) == 2 || return false
+        length(argtypes) == 1 || return false
         return isa(rt, Const)
     end
     return false