1 files changed, 33 insertions, 0 deletions
diff --git a/unit-tests/suff-rebuild.mk b/unit-tests/suff-rebuild.mk
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index 000000000000..d190eaf4c6e8
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+++ b/unit-tests/suff-rebuild.mk
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+# $NetBSD: suff-rebuild.mk,v 1.2 2020/10/18 16:12:39 rillig Exp $
+#
+# Demonstrates what happens to transformation rules (called inference rules
+# by POSIX) when all suffixes are deleted.
+
+all: suff-rebuild-example
+
+.SUFFIXES:
+
+.SUFFIXES: .a .b .c
+
+suff-rebuild-example.a:
+	: from nothing to a
+
+.a.b:
+	: from a to b
+.b.c:
+	: from b to c
+.c:
+	: from c to nothing
+
+# XXX: At a quick glance, the code in SuffScanTargets looks as if it were
+# possible to delete the suffixes in the middle of the makefile, add back
+# the suffixes from before, and have the transformation rules preserved.
+#
+# As of 2020-09-25, uncommenting the following line results in the error
+# message "don't know how to make suff-rebuild-example" though.
+#
+#.SUFFIXES:
+
+# Add the suffixes back.  It should not matter that the order of the suffixes
+# is different from before.
+.SUFFIXES: .c .b .a