No error for missing semicolon before "then"

[Ulrich Mueller]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: x86_64-pc-linux-gnu-gcc
Compilation CFLAGS: -march=native -ggdb -O2 -pipe
uname output: Linux urania 6.6.47-gentoo #1 SMP Mon Aug 19 15:25:50 CEST 2024 
x86_64 AMD Ryzen 7 PRO 7730U with Radeon Graphics AuthenticAMD GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 5.2
Patch Level: 32
Release Status: release

Description:
        The following command does not error out, in spite of a
        semicolon missing before "then":
        $ if [[ x ]] then :; fi

        Previous versions (e.g. 4.4.23) used to report an error:
        bash: syntax error near unexpected token `then'

Repeat-By:
        $ if [[ x ]] then :; fi