.PHONY: all

all: case.1 case.2 case.3

a: void

# 1 - existing file
#
%.1: void
	@false

%.1: makefile
	@true


# 2 - phony
#
%.2: void
	@false

%.2: 2.phony
	@true

.PHONY: 2.phony


# 3 - implicit-phony
#
%.3: void
	@false

%.3: 3.implicit-phony
	@true

3.implicit-phony: