parens are not optional in guard chains that have || operators#2224
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| r[expr.if.chains.or] | ||
| If any condition operand is a `let` pattern, then none of the condition operands can be a `||` [lazy boolean operator expression][expr.bool-logic] due to ambiguity and precedence with the `let` scrutinee. If a `||` expression is needed, then parentheses can be used. For example: | ||
| If any condition operand is a `let` pattern, then none of the condition operands can be a `||` [lazy boolean operator expression][expr.bool-logic] due to ambiguity and precedence with the `let` scrutinee. If a `||` expression is needed, then parentheses must be used. For example: |
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I don't think it is correct to use "must" here. This is saying that this is an option for how to work around the limitation. For example, you could sometimes use curly braces, or lift parts out to a variable, or don't use chains.
I think the correct change would be to move this statement out to an example block like the other one, since it isn't a language rule.
Also - Make an example follow convention (mark with `[!EXAMPLE]`) - Change formatting to place comment closer to its code
This is to match the original wording and to match the wording in expr.match.guard.chains.or. Parentheses are not necessarily the only way to work around this limitation. For example, you could sometimes use curly braces, or lift parts out to a variable, or don't use chains.
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Update books ## rust-lang/reference 10 commits in ad35aca481751a06afeb23820a672b0f3b11a476..01b0ee707f4571e803c8b2c471d8335a448f5d60 2026-05-31 18:52:24 UTC to 2026-05-20 14:06:08 UTC - Update `naked` to use the attribute template (rust-lang/reference#1908) - Update link_name for updated restrictions (rust-lang/reference#2268) - parens are not optional in guard chains that have || operators (rust-lang/reference#2224) - Document `target_has_atomic_primitive_alignment` (rust-lang/reference#2273) - Fix grammar rules pertaining to obsolete range patterns (rust-lang/reference#2259) - Unwrap a few remaining chapters (rust-lang/reference#2276) - Guarantee alignment of `repr(C)` structs with no fields (rust-lang/reference#2264) - avoid using 'place projection' for only some of the projections (rust-lang/reference#2253) - add xtask doctest (rust-lang/reference#2255) - Grammar: Don't allow inner attrs in certain block expressions (rust-lang/reference#2269) ## rust-lang/rust-by-example 7 commits in 898f0ac1479223d332309e0fce88d44b39927d28..d3117f6c873acbbf331c1d510371d061dfcc975c 2026-06-01 14:19:19 UTC to 2026-05-25 13:19:23 UTC - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2018) - Match comment module & file order (rust-lang/rust-by-example#2009) - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2011) - Update expression.md: renamed variable x_cube to x_cubed (rust-lang/rust-by-example#2012) - Update comment.md - Fixed comments related to asterisk column (rust-lang/rust-by-example#2013) - Minor typo in meta.md (rust-lang/rust-by-example#2016) - Fix erroroneous implication (rust-lang/rust-by-example#2017)
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Update books ## rust-lang/reference 10 commits in ad35aca481751a06afeb23820a672b0f3b11a476..01b0ee707f4571e803c8b2c471d8335a448f5d60 2026-05-31 18:52:24 UTC to 2026-05-20 14:06:08 UTC - Update `naked` to use the attribute template (rust-lang/reference#1908) - Update link_name for updated restrictions (rust-lang/reference#2268) - parens are not optional in guard chains that have || operators (rust-lang/reference#2224) - Document `target_has_atomic_primitive_alignment` (rust-lang/reference#2273) - Fix grammar rules pertaining to obsolete range patterns (rust-lang/reference#2259) - Unwrap a few remaining chapters (rust-lang/reference#2276) - Guarantee alignment of `repr(C)` structs with no fields (rust-lang/reference#2264) - avoid using 'place projection' for only some of the projections (rust-lang/reference#2253) - add xtask doctest (rust-lang/reference#2255) - Grammar: Don't allow inner attrs in certain block expressions (rust-lang/reference#2269) ## rust-lang/rust-by-example 7 commits in 898f0ac1479223d332309e0fce88d44b39927d28..d3117f6c873acbbf331c1d510371d061dfcc975c 2026-06-01 14:19:19 UTC to 2026-05-25 13:19:23 UTC - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2018) - Match comment module & file order (rust-lang/rust-by-example#2009) - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2011) - Update expression.md: renamed variable x_cube to x_cubed (rust-lang/rust-by-example#2012) - Update comment.md - Fixed comments related to asterisk column (rust-lang/rust-by-example#2013) - Minor typo in meta.md (rust-lang/rust-by-example#2016) - Fix erroroneous implication (rust-lang/rust-by-example#2017)
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Update books ## rust-lang/reference 10 commits in ad35aca481751a06afeb23820a672b0f3b11a476..01b0ee707f4571e803c8b2c471d8335a448f5d60 2026-05-31 18:52:24 UTC to 2026-05-20 14:06:08 UTC - Update `naked` to use the attribute template (rust-lang/reference#1908) - Update link_name for updated restrictions (rust-lang/reference#2268) - parens are not optional in guard chains that have || operators (rust-lang/reference#2224) - Document `target_has_atomic_primitive_alignment` (rust-lang/reference#2273) - Fix grammar rules pertaining to obsolete range patterns (rust-lang/reference#2259) - Unwrap a few remaining chapters (rust-lang/reference#2276) - Guarantee alignment of `repr(C)` structs with no fields (rust-lang/reference#2264) - avoid using 'place projection' for only some of the projections (rust-lang/reference#2253) - add xtask doctest (rust-lang/reference#2255) - Grammar: Don't allow inner attrs in certain block expressions (rust-lang/reference#2269) ## rust-lang/rust-by-example 7 commits in 898f0ac1479223d332309e0fce88d44b39927d28..d3117f6c873acbbf331c1d510371d061dfcc975c 2026-06-01 14:19:19 UTC to 2026-05-25 13:19:23 UTC - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2018) - Match comment module & file order (rust-lang/rust-by-example#2009) - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2011) - Update expression.md: renamed variable x_cube to x_cubed (rust-lang/rust-by-example#2012) - Update comment.md - Fixed comments related to asterisk column (rust-lang/rust-by-example#2013) - Minor typo in meta.md (rust-lang/rust-by-example#2016) - Fix erroroneous implication (rust-lang/rust-by-example#2017)
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Rollup merge of #157265 - rustbot:docs-update, r=ehuss Update books ## rust-lang/reference 10 commits in ad35aca481751a06afeb23820a672b0f3b11a476..01b0ee707f4571e803c8b2c471d8335a448f5d60 2026-05-31 18:52:24 UTC to 2026-05-20 14:06:08 UTC - Update `naked` to use the attribute template (rust-lang/reference#1908) - Update link_name for updated restrictions (rust-lang/reference#2268) - parens are not optional in guard chains that have || operators (rust-lang/reference#2224) - Document `target_has_atomic_primitive_alignment` (rust-lang/reference#2273) - Fix grammar rules pertaining to obsolete range patterns (rust-lang/reference#2259) - Unwrap a few remaining chapters (rust-lang/reference#2276) - Guarantee alignment of `repr(C)` structs with no fields (rust-lang/reference#2264) - avoid using 'place projection' for only some of the projections (rust-lang/reference#2253) - add xtask doctest (rust-lang/reference#2255) - Grammar: Don't allow inner attrs in certain block expressions (rust-lang/reference#2269) ## rust-lang/rust-by-example 7 commits in 898f0ac1479223d332309e0fce88d44b39927d28..d3117f6c873acbbf331c1d510371d061dfcc975c 2026-06-01 14:19:19 UTC to 2026-05-25 13:19:23 UTC - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2018) - Match comment module & file order (rust-lang/rust-by-example#2009) - Fix Spanish translation typos in es.po (rust-lang/rust-by-example#2011) - Update expression.md: renamed variable x_cube to x_cubed (rust-lang/rust-by-example#2012) - Update comment.md - Fixed comments related to asterisk column (rust-lang/rust-by-example#2013) - Minor typo in meta.md (rust-lang/rust-by-example#2016) - Fix erroroneous implication (rust-lang/rust-by-example#2017)
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