Fix #650: StrataVerify Panic in Type inference#730
Merged
Conversation
…pe parameter inference When a function's type parameter could not be inferred (e.g., due to an earlier type mismatch), inferType would panic with 'Cannot instantiate type'. This occurred because the default Tree (produced when type inference fails) generates an .op argument where .type was expected. Replace the panic! in the instTypeM callback with a logError call and a default type return, allowing elaboration to continue and report the actual type errors to the user. Add a regression test reproducing the exact program from the issue.
This comment was marked as resolved.
This comment was marked as resolved.
Sorry, something went wrong.
atomb
approved these changes
Apr 2, 2026
joscoh
approved these changes
Apr 3, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes #650
Problem
inferTypepanicked with "Cannot instantiate type" when a function's type parameter could not be inferred during DDM elaboration. This happened when an earlier type mismatch (e.g., from a||expression being parsed where a datatype was expected) left a type parameter slot unfilled, causing a default placeholder to appear where a.typeargument was expected.Solution
Replace the
panic!in theinstTypeMcallback withininferTypewith alogErrorcall and a default type return. This allows elaboration to continue and report the actual type errors to the user instead of crashing.Testing