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Merge #11623
11623: fix: Add type variable table to InferenceTableSnapshot r=flodiebold a=tysg
Fixes #11601.
I observed that removing the `rollback` line in https://github.com/rust-analyzer/rust-analyzer/commit/6fc3d3aa4cbf637d748c60cfdbb98b5f6a040576 fixes the issue.
Looking at the stacktrace, I believe not restoring `type_variable_table` causes `type_variable_table` and `var_unification_table` to go out of sync, then when `hir_ty::infer::unify::InferenceTable::new_var` tries to extend `type_variable_table` to be the same length as `var_unification_table`, problems will arise.
However, I cannot pinpoint exactly how or where the vector capacity overflow happens, so my understanding might not be correct after all.
Co-authored-by: Tianyi Song <[email protected]>
| -rw-r--r-- | crates/hir_ty/src/infer/unify.rs | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs index 21b48b9d80..8a6c34b493 100644 --- a/crates/hir_ty/src/infer/unify.rs +++ b/crates/hir_ty/src/infer/unify.rs @@ -140,7 +140,8 @@ pub(crate) struct InferenceTable<'a> { pub(crate) struct InferenceTableSnapshot { var_table_snapshot: chalk_solve::infer::InferenceSnapshot<Interner>, - // FIXME: snapshot type_variable_table, pending_obligations? + // FIXME: snapshot pending_obligations? + type_variable_table_snapshot: Vec<TypeVariableData>, } impl<'a> InferenceTable<'a> { @@ -356,12 +357,14 @@ impl<'a> InferenceTable<'a> { } pub(crate) fn snapshot(&mut self) -> InferenceTableSnapshot { - let snapshot = self.var_unification_table.snapshot(); - InferenceTableSnapshot { var_table_snapshot: snapshot } + let var_table_snapshot = self.var_unification_table.snapshot(); + let type_variable_table_snapshot = self.type_variable_table.clone(); + InferenceTableSnapshot { var_table_snapshot, type_variable_table_snapshot } } pub(crate) fn rollback_to(&mut self, snapshot: InferenceTableSnapshot) { self.var_unification_table.rollback_to(snapshot.var_table_snapshot); + self.type_variable_table = snapshot.type_variable_table_snapshot; } /// Checks an obligation without registering it. Useful mostly to check |