C-style escapes within substitution expansion

[David Sines]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash'
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -g -O2
uname output: Linux perseus 3.0.0-1 #1 Thu Aug 11 12:53:44 BST 2011
i686 GNU/Linux
Machine Type: i686-pc-linux-gnu

Bash Version: 4.3
Patch Level: 0
Release Status: release

Description:
        When invoked as sh, bash 4.3.0 doesn't interpret C-style escapes
within double-quoted substitution expansions ("${var/$'what'/ever}").

Repeat-By:

  bash -c "a=-@- ; echo \${a/\$'\\x40'/+} ; echo \"\${a/\$'\\x40'/+}\""
  -+-
  -+-
  sh   -c "a=-@- ; echo \${a/\$'\\x40'/+} ; echo \"\${a/\$'\\x40'/+}\""
  -+-
  -@-