private fun check_method_signature(modelbuilder: ModelBuilder, mpropdef: MMethodDef)
	do
		var mclassdef = mpropdef.mclassdef
		var mmodule = mclassdef.mmodule
		var nsig = self.n_type
		var mysignature = mpropdef.msignature
		if mysignature == null then return # Error thus skiped

		# Lookup for signature in the precursor
		# FIXME all precursors should be considered
		if not mpropdef.is_intro then
			var msignature = mpropdef.mproperty.intro.msignature
			if msignature == null then return

			if mysignature.arity != msignature.arity then
				var node: ANode
				if nsig != null then node = nsig else node = self
				modelbuilder.error(node, "Redef Error: expected {msignature.arity} parameter(s) for `{mpropdef.mproperty.name}{msignature}`; got {mysignature.arity}. See introduction at `{mpropdef.mproperty.full_name}`.")
				return
			end
			var precursor_ret_type = msignature.return_mtype
			var ret_type = mysignature.return_mtype
			if ret_type != null and precursor_ret_type == null then
				var node: ANode
				if nsig != null then node = nsig else node = self
				modelbuilder.error(node, "Redef Error: `{mpropdef.mproperty}` is a procedure, not a function.")
				return
			end

			if mysignature.arity > 0 then
				# Check parameters types
				for i in [0..mysignature.arity[ do
					var myt = mysignature.mparameters[i].mtype
					var prt = msignature.mparameters[i].mtype
					var node: ANode
					if nsig != null then node = nsig else node = self
					if not modelbuilder.check_sametype(node, mmodule, mclassdef.bound_mtype, myt, prt) then
						modelbuilder.error(node, "Redef Error: expected `{prt}` type for parameter `{mysignature.mparameters[i].name}'; got `{myt}`.")
					end
				end
			end
			if precursor_ret_type != null then
				var node: ANode
				if nsig != null then node = nsig else node = self
				if ret_type == null then
					# Inherit the return type
					ret_type = precursor_ret_type
				else if not modelbuilder.check_subtype(node, mmodule, mclassdef.bound_mtype, ret_type, precursor_ret_type) then
					modelbuilder.error(node, "Redef Error: expected `{precursor_ret_type}` return type; got `{ret_type}`.")
				end
			end
		end
	end