PLC-lang/rusty

Evaluate all array elements before returning an overflow error

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#872 opened on Jun 12, 2023

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good first issuelow-priority

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Description

Overflow checks for arrays currently stop evaluating after the first element that overflows, e.g.

FUNCTION main : DINT
  VAR
    arr : ARRAY[0..4] OF UDINT := [-1, -2, -3, 4, -5];
  END_VAR
END_FUNCTION

will return

error: This will overflow for type UDINT
  ┌─ target/demo.st:3:36
  │
3 │     arr : ARRAY[0..4] OF UDINT := [-1, -2, -3, 4, -5];
  │                                    ^^ This will overflow for type UDINT

Instead of only reporting -1 here, one would expect to also receive an error message for -2, -3 and -5. Fixing this will require some tweaks in the evalute_with_target_hint function, more specifically this line https://github.com/PLC-lang/rusty/blob/c33bc5f04dcf9294f31920c961eb5050362f15a8/src/resolver/const_evaluator.rs#L341

Contributor guide

Research direction
Modify the `evaluate with target hint` function in `src/resolver/const evaluator.rs` to collect all overflow errors for array elements and report them together instead of stopping at the first overflow.
Tech stack
rust
Domain
compilers
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Rust
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70