Description of problem:
The following scripts are making bash to leak memory (originally reproducers for ksh memleaks). Also, the scripts run significantly slower under bash than with ksh (may be caused by the leaks, though).

$ cat repr1.ksh
#!/usr/bin/ksh

function _hash {
        typeset w=([abc]=1 [def]=31534 [xyz]=42)
        print -u2 $w 2>&-
        # accessing the var will leak
}
function _array {
        typeset w=(1 31534 42)
        print -u2 $w 2>&-
        # unset w will prevent leak
}

pmap -x $$ |tail -1
for (( j=0; j<100; j++)); do
        for (( i=0; i<10000; i++)); do
               _hash
        done
        pmap -x $$ |tail -1
done
sleep 1

$ cat repr4.ksh
#!/usr/bin/ksh

function _hash {
        typeset w=([abc]=1 [def]=31534 [xyz]=42)
        print -u2 $w 2>&-
        # accessing the var will leak
}
function _array {
        typeset w=(1 31534 42)
        print -u2 $w 2>&-
        # unset w will prevent leak
}

pmap -x $$ |tail -1
for (( j=0; j<100; j++)); do
        for (( i=0; i<10000; i++)); do
               _array
        done
        pmap -x $$ |tail -1
done
sleep 1

Version-Release number of selected component (if applicable):
bash-4.2.46-19.el7

How reproducible:
Always


Steps to Reproduce:
1. run the scripts from description
2.
3.

Actual results:
Memory usage grows quickly:
$ bash repr1.ksh
total kB          115060    3152     252
total kB          117964    6096    3196
total kB          120868    8912    6012
total kB          123640   11724    8824
total kB          126412   14536   11636
^C
$ bash repr4.ksh
total kB          115060    3152     256
total kB          117964    6096    3200
total kB          120868    8912    6016
total kB          123640   11724    8828
total kB          126412   14536   11640
^C
$


Expected results:
Steady memory usage as is with ksh:
$ ksh repr1.ksh
total kB          116848    1728     292
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
total kB          116848    1860     312
^C
$ ksh repr4.ksh
total kB          116848    1720     288
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
total kB          116848    1852     308
^C



Additional info: