Parameter expansion oddity

[Tim Waugh]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: i386-redhat-linux-gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu' 
-DCONF_VENDOR='redhat' -DSHELL -DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib 
-D_GNU_SOURCE  -O2 -g -pipe -march=i386 -mcpu=i686
uname output: Linux meme.surrey.redhat.com 2.4.20-13.9 #1 Mon May 12 10:55:37 
EDT 2003 i686 i686 i386 GNU/Linux
Machine Type: i386-redhat-linux-gnu

Bash Version: 2.05b
Patch Level: 0
Release Status: release

Description:
        ${VAR:+WORD} may be replaced by the expansion of WORD.  But there
        seems to be no way of creating double quotes in this expansion, since
        both quote removal and escaping behave oddly.

Repeat-By:
        Trying to get output: "bar"

FOO=bar cat <<EOF
${FOO:+"$FOO"}
EOF
..produces: bar

FOO=bar cat <<EOF
${FOO:+\"$FOO\"}
EOF
..produces: \"bar\"

FOO=bar cat <<EOF
${FOO:+'"'$FOO'"'}
EOF
..produces: ''bar''

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