[AkasakaJelos]

The keyword “low” in Gobra denotes low security in the non-interference model. Therefore, if “low” is defined as a variable, Gobra will produce the following compilation error due to a presumed keyword clash:

No changes detected in the antlr4 files. Skipping parser generation.
[info] running (fork) viper.gobra.GobraRunner -i /.../exercises/tutorial7.go
[info] Gobra 1.1-SNAPSHOT (351ad1fe@(detached))
[info] (c) Copyright ETH Zurich 2012 - 2024
[info] Verifying package .. - exercises [14:21:29]
[info] Error at: </.../exercises/tutorial7.go:14:5> no viable alternative at input 'low :='
[info] 	low := 0
[info]  ^^^^^^^^
[info] Gobra found 1 error.
[info]
[error] Nonzero exit code returned from runner: 1
[error] (Compile / run) Nonzero exit code returned from runner: 1
[error] Total time: 10 s, completed 25 Jan 2026, 14:21:30

The best approach is to rename "low" to "lowElement" and "high" to "highElement". I left "mid" unchanged, since it is already unambiguous :)

[jcp19]

Hi Kwok, thank you for the PR, it is much appreciated :)