viperproject / viperproject/silver
Incorrect positions in Method AST nodes
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- Dominant language
- Scala
- Stars
- 100
- Forks
- 53
- Avg merge
- 8h 10m
- Merged PRs (30d)
- 2
Description
SilFrontend generates AST nodes with incorrect positions. In particular, the start position of methods is wrong (seems to be the same as their end position for some reason).
This is a critical bug because currently, the soundness of the caching mechanism in ViperServer (hence, also in Viper IDE and all of the frontend verifiers that use ViperServer) depends on the method position information.
To reproduce the problem, simply execute sbt testOnly *AstPositionsTests to run the test defined in src/test/scala/AstPositionsTests.scala.
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First steps
- Read the whole issue, then the project's contributing guide.
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- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Run sbt testOnly *AstPositionsTests and inspect src/test/scala/AstPositionsTests.scala to understand the expected method positions. Trace how SilFrontend creates method AST nodes and compare their start and end positions. Done means the position tests pass and method positions are correct for the caching use described.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- scala
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100