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# $NetBSD: use-inference.mk,v 1.1 2020/08/09 16:32:28 rillig Exp $
#
# Demonstrate that .USE rules do not have an effect on inference rules.
# At least not in the special case where the inference rule does not
# have any associated commands.
.SUFFIXES:
.SUFFIXES: .from .to
all: use-inference.to
verbose: .USE
@echo 'Verbosely making $@ out of $>'
.from.to: verbose
# Since this inference rule does not have any associated commands, it
# is ignored.
#
# @echo 'Building $@ from $<'
use-inference.from: # assume it exists
@echo 'Building $@ from nothing'
# Possible but unproven explanation:
#
# The main target is "all", which depends on "use-inference.to".
# The inference connects the .from to the .to file, otherwise make
# would not know that the .from file would need to be built.
#
# The .from file is then built.
#
# After this, make stops since it doesn't know how to make the .to file.
# This is strange since make definitely knows about the .from.to suffix
# inference rule. But it seems to ignore it, maybe because it doesn't
# have any associated commands.
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