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cf7041186c
Properly track `DepNode`s in trait evaluation provisional cache Fixes #92987 During evaluation of an auto trait predicate, we may encounter a cycle. This causes us to store the evaluation result in a special 'provisional cache;. If we later end up determining that the type can legitimately implement the auto trait despite the cycle, we remove the entry from the provisional cache, and insert it into the evaluation cache. Additionally, trait evaluation creates a special anonymous `DepNode`. All queries invoked during the predicate evaluation are added as outoging dependency edges from the `DepNode`. This `DepNode` is then store in the evaluation cache - if a different query ends up reading from the cache entry, it will also perform a read of the stored `DepNode`. As a result, the cached evaluation will still end up (transitively) incurring all of the same dependencies that it would if it actually performed the uncached evaluation (e.g. a call to `type_of` to determine constituent types). Previously, we did not correctly handle the interaction between the provisional cache and the created `DepNode`. Storing an evaluation result in the provisional cache would cause us to lose the `DepNode` created during the evaluation. If we later moved the entry from the provisional cache to the evaluation cache, we would use the `DepNode` associated with the evaluation that caused us to 'complete' the cycle, not the evaluatoon where we first discovered the cycle. As a result, future reads from the evaluation cache would miss some incremental compilation dependencies that would have otherwise been added if the evaluation was *not* cached. Under the right circumstances, this could lead to us trying to force a query with a no-longer-existing `DefPathHash`, since we were missing the (red) dependency edge that would have caused us to bail out before attempting forcing. This commit makes the provisional cache store the `DepNode` create during the provisional evaluation. When we move an entry from the provisional cache to the evaluation cache, we create a *new* `DepNode` that has dependencies going to *both* of the evaluation `DepNodes` we have available. This ensures that cached reads will incur all of the necessary dependency edges. |
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| .. | ||
| rustc | ||
| rustc_apfloat | ||
| rustc_arena | ||
| rustc_ast | ||
| rustc_ast_lowering | ||
| rustc_ast_passes | ||
| rustc_ast_pretty | ||
| rustc_attr | ||
| rustc_borrowck | ||
| rustc_builtin_macros | ||
| rustc_codegen_cranelift | ||
| rustc_codegen_gcc | ||
| rustc_codegen_llvm | ||
| rustc_codegen_ssa | ||
| rustc_const_eval | ||
| rustc_data_structures | ||
| rustc_driver | ||
| rustc_error_codes | ||
| rustc_errors | ||
| rustc_expand | ||
| rustc_feature | ||
| rustc_fs_util | ||
| rustc_graphviz | ||
| rustc_hir | ||
| rustc_hir_pretty | ||
| rustc_incremental | ||
| rustc_index | ||
| rustc_infer | ||
| rustc_interface | ||
| rustc_lexer | ||
| rustc_lint | ||
| rustc_lint_defs | ||
| rustc_llvm | ||
| rustc_log | ||
| rustc_macros | ||
| rustc_metadata | ||
| rustc_middle | ||
| rustc_mir_build | ||
| rustc_mir_dataflow | ||
| rustc_mir_transform | ||
| rustc_monomorphize | ||
| rustc_parse | ||
| rustc_parse_format | ||
| rustc_passes | ||
| rustc_plugin_impl | ||
| rustc_privacy | ||
| rustc_query_impl | ||
| rustc_query_system | ||
| rustc_resolve | ||
| rustc_save_analysis | ||
| rustc_serialize | ||
| rustc_session | ||
| rustc_span | ||
| rustc_symbol_mangling | ||
| rustc_target | ||
| rustc_trait_selection | ||
| rustc_traits | ||
| rustc_ty_utils | ||
| rustc_type_ir | ||
| rustc_typeck | ||