Avoid stack overflow when printing unevaluated const #72341
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Fixes rust-lang#68104 When printing the DefPath for an unevaluated const, we may end up trying to print the same const again. To avoid infinite recursion, we use the 'verbose' format when we try to re-entrantly print a const. This ensures that the pretty-printing process will always terminate.
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| // Braces around const expression causes crash | ||
| impl Num<{5}> { |
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The braces shouldn't matter, I wonder if this is a bug (cc @varkor).
What you want is to use an expression, like 2+3, so that it definitely requires evaluation.
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We currently don't look into blocks for literals, It seems like we only do it for params at the moment
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Will get a PR ready which cleans this up.
edit: we may not actually want this for now, as being more aggressive here may mask some otherwise found issues with ConstKind::Unevaluated.
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We shouldn't need braces here: arbitrary expressions should work, and {5} is an expression.
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The braces are needed to trigger the original ICE, so I included them in the test
| // const. This ensures that we never end up trying to recursively | ||
| // print a const that we're already printing. | ||
| // See issue #68104 for more details | ||
| self = with_no_const_path(|| { |
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Can you try with_forced_impl_filename_line instead? It should also work since I believe the problem here is the pretty-printing of impl paths.
Wait. Hang on. Why would this ever print paths?!
The bug is probably in metadata encoding/decoding. AnonConsts shouldn't turn into DefKind::Const.
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Closing in favor of #72600 as per @eddyb's comment: #72341 (comment) |
Fixes #68104
When printing the DefPath for an unevaluated const, we may end up trying
to print the same const again. To avoid infinite recursion, we use the
'verbose' format when we try to re-entrantly print a const. This ensures
that the pretty-printing process will always terminate.