Fix #12904 FN unusedFunction with function named like unknown type (#… #19332

Job	Run time
build_cmake (alpine:3.23, false, false)	4m 24s
build_cmake (ubuntu:24.04, true, true)	5m 38s
build_cmake (ubuntu:25.10, true, true)	2m 58s
build_make (alpine:3.23)	5m 59s
build_make (ubuntu:25.10)	3m 15s
build_make (ubuntu:24.04)	2m 53s
	25m 7s

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