eb8f2586eb
Fixes issue #43205: ICE in Rvalue::Len evaluation. - fixes evaluation of array length for zero-sized type referenced by rvalue operand. - adds test to verify fix. *Cause of the issue*. Zero-sized aggregates are handled as operands, not lvalues. Therefore while visiting `Assign` statement by `LocalAnalyser`, `mark_as_lvalue()` is not called for related `Local`. This behaviour is controlled by `rvalue_creates_operand()` method. As result it causes error later, when rvalue operand is evaluated in `trans_rvalue_operand()` while handling `Rvalue::Len` case. Array length evaluation invokes `trans_lvalue()` which expects referenced `Local` to be value, not operand. *How it is fixed*. In certain cases result of `Rvalue::Len` can be evaluated without calling `trans_lvalue()`. Method `evaluate_array_len()` is introduced to handle length evaluation for zero-sized types referenced by Locals. *Some concerns*. - `trans_lvalue()` has two other entry points in `rvalue.rs`: it is invoked while handling `Rvalue::Ref` and `Rvalue::Discriminant`. There is a chance those may produce the same issue, but I've failed to write a specific test that leads to this. - `evaluate_array_len()` performs the same check (matches lvalue and `Local`), which is performed again in `trans_lvalue()`. Without changing `trans_lvalue()` signature to make it aware that caller deals with rvalue, it seems there is no cheap solution to avoid this check. |
||
|---|---|---|
| .. | ||
| codegen | ||
| codegen-units | ||
| compile-fail | ||
| compile-fail-fulldeps | ||
| debuginfo | ||
| incremental | ||
| mir-opt | ||
| parse-fail | ||
| pretty | ||
| run-fail | ||
| run-fail-fulldeps | ||
| run-make | ||
| run-pass | ||
| run-pass-fulldeps | ||
| run-pass-valgrind | ||
| rustdoc | ||
| ui | ||
| ui-fulldeps | ||
| COMPILER_TESTS.md | ||