Integer (re)declaration keeps string values

[andrej]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -march=x86-64 -mtune=generic -O2 -pipe -fno-plt 
-DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' 
-DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' 
-DSYS_BASH_LOGOUT='/etc/bash.bash_logout' -DNON_INTERACTIVE_LOGIN_SHELLS 
-Wno-parentheses -Wno-format-security
uname output: Linux charon 5.6.15-arch1-1-user-regd #1 SMP PREEMPT Sat, 30 May 
2020 12:13:36 +0000 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 5.0
Patch Level: 17
Release Status: release

Description:
        Integer variables don't get (re)parsed when (re)declared.

Repeat-By:
        a=z
        declare -i a
        echo $a  # z (I'd expect emptiness or 0)