Makefile overriding recipe error when string is used inside of echo - makefile

Question

I have the following Makefile and I get an error when I use all target. I am not sure what is the root cause of the problem.
APSTOP= ../..
VERSION=2.12.8
SVERSION=2.12
SCALAC= /afs/package/scala/scala-${VERSION}/common/bin/scalac
APSLIB = ${APSTOP}/lib/aps-library-${SVERSION}.jar
COOLCOMPILERDIR= /afs/project/cool/scala
SCALAFLAGS= -cp .:${APSLIB}
SCALACFLAGS= ${SCALAFLAGS}
APS2SCALA = ${APSTOP}/bin/aps2scala
APS2SCALAFLAGS = -p ..:${APSTOP}/base -G
SCALASRC = cool-symbol.handcode.scala cool-semant-driver.scala cool-handcode.scala cool-noinherit-semant-driver.scala
SCALAGEN = cool-symbol.scala cool-tree.scala \
cool-noinherit-semant.scala cool-dynamic-semant.scala
SCALACOPY= basic.scala A2I.scala \
CoolTokens.scala CoolScanner.scala CoolOptions.scala \
CoolParser.scala
SCALAHAND = CoolCompiler.scala
EXAMPLEDIR = ../examples
.PHONY: all clean src
src : ${SCALASRC}
all : ${SCALAGEN}
all : cool_symbol_implicit.class \
cool_tree_implicit.class \
cool_noinherit_semant_implicit.class \
cool_dynamic_semant_implicit.class
%.scala : ../%.aps
${APS2SCALA} ${APS2SCALAFLAGS} $*
cool-symbol.scala : ../cool-symbol.aps
${APS2SCALA} ${APS2SCALAFLAGS} --omit SYMBOL --omit gensym cool-symbol
%_implicit.class : %.scala
${SCALAC} ${SCALACFLAGS} $*.scala
cool_symbol_implicit.class : cool-symbol.scala cool-symbol.handcode.scala
${SCALAC} ${SCALACFLAGS} cool-symbol.scala cool-symbol.handcode.scala
cool_tree_implicit.class : cool-tree.scala cool_symbol_implicit.class
${SCALAC} ${SCALACFLAGS} cool-tree.scala
cool_noinherit_semant_implicit.class : cool-noinherit-semant.scala
${SCALAC} ${SCALACFLAGS} $<
cool_dynamic_semant_implicit.class : cool-dynamic-semant.scala
${SCALAC} ${SCALACFLAGS} $<
%.scala : RCS/%.scala,v
co $<
.PHONY: %.run
%.run : %.class
scala ${SCALAFLAGS} $*
.PHONY: %.compile
%.compile : %.scala
scalac ${SCALACFLAGS} $*.scala
.PHONY: %.semant
%.semant : ${EXAMPLEDIR}/%.cool Semant.class
scala ${SCALAFLAGS} CoolCompiler $<
.PHONY: %.debug
%.debug : ${EXAMPLEDIR}/%.cool Semant.class
scala ${SCALAFLAGS} CoolCompiler -s $<
COOLCOMPILERSCALA = \
cool-symbol.scala cool-symbol.handcode.scala cool-tree.scala \
cool-handcode.scala ${SCALACOPY} \
cool-dummy-semant-driver.scala ${SCALAHAND}
${SCALACOPY} :
echo "import cool_implicit._" | cat - ${COOLCOMPILERDIR}/$# > $#
CoolParser.scala :
echo "import cool_implicit._" | cat - ${COOLCOMPILERDIR}/$# > $#.tmp
sed 's/result.set_inheritablep(/t_Tree.s_inheritablep(result,/' \
< $#.tmp > $#
cool-parser-${SVERSION}.jar : ${COOLCOMPILERSCALA}
#rm -f *.class
${SCALAC} -deprecation ${SCALACFLAGS} ${COOLCOMPILERSCALA}
jar cvf $# *.class
install: cool-parser-${SVERSION}.jar
cp cool-parser-${SVERSION}.jar ../../lib/.
clean:
rm -f *.class ${SCALAGEN} ${SCALACOPY} *.jar
Error:
Makefile:79: warning: overriding recipe for target 'CoolParser.scala'
Makefile:76: warning: ignoring old recipe for target 'CoolParser.scala'
make: Nothing to be done for 'src'.

Answer 1

That is not an error: if it was an error the build would have failed. This build succeeded. In make error messages contain ***. This is just a warning about a weird thing in your makefile.
To understand it you just have to look at the lines in your makefile that make is complaining about, and read the message it printed.
You have this variable set:
SCALACOPY= basic.scala A2I.scala \
CoolTokens.scala CoolScanner.scala CoolOptions.scala \
CoolParser.scala
So this variable contains CoolParser.scala.
Next at Makefile line 76, you have this:
${SCALACOPY} :
echo "import cool_implicit._" | cat - ${COOLCOMPILERDIR}/$# > $#
This defines rules telling make how to build all the targets in the variable SCALACOPY, including CoolParser.scala.
Then at Makefile line 79, you have this:
CoolParser.scala :
echo "import cool_implicit._" | cat - ${COOLCOMPILERDIR}/$# > $#.tmp
sed 's/result.set_inheritablep(/t_Tree.s_inheritablep(result,/' \
< $#.tmp > $#
This tells make ANOTHER rule also to build CoolParser.scala, which you already provided a rule for; make will drop the first rule and use the second rule, but it will also give you a warning message telling you about it because this is very unusual and not usually what you want to do:
Makefile:79: warning: overriding recipe for target 'CoolParser.scala'
Makefile:76: warning: ignoring old recipe for target 'CoolParser.scala'