Bug with constant propagation

[ahpaleus]

Describe the bug
The metavariable-comparison does not work as expected. It should also match when a value in the index 'comes from' a variable.

To Reproduce
https://semgrep.dev/playground/s/NbJPp

Expected behavior
The 9th line should be caught.

What is the priority of the bug to you?

• P0: blocking your adoption of Semgrep or workflow
• P1: important to fix or quite annoying
• P2: regular bug that should get fixed

[mjambon]

Thanks for reporting this bug. It looks like constant propagation doesn't work for variables occurring in array slices e.g. x isn't replaced by its value in a[1:x] but it works for simple array indices such as a[x].

Here's the playground link for future reference: https://semgrep.dev/playground/s/ReAdE