Arithmetic pow results incorrect in arithmetic expansion.

[Hyunho Cho]

Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2
-fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul
10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu

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

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i have tested below in gnome calculator, Qalculate, gawk, perl
and all results in -4 but bash is 4

$ awk 'BEGIN { print -2 ^ 2 }'
-4

$ perl -E 'say -2 ** 2'
-4

$ echo $(( -2 ** 2 ))                     # only bash results in 4
4