Document temporary scoping for destructuring assignments #1992
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Revised. @dianne, does this look correct? |
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Looks good to me. Thanks! |
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Among other things, let's break up the one admonition into two admonitions, as there are separate ideas here; within the admonitions, let's pull more of the explanation out of code comments and into the main narrative; let's add rule identifiers for these admonitions; and let's reference these admonitions from the relevant places in the destructors chapter.
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Thanks @dianne. |
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Rollup merge of #146898 - rustbot:docs-update, r=ehuss Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Update books ## rust-lang/book 1 commits in 3e9dc46aa563ca0c53ec826c41b05f10c5915925..33f1af40cc44dde7e3e892f7a508e6f427d2cbc6 2025-09-15 16:10:14 UTC to 2025-09-15 16:10:14 UTC - Release trpl 0.3 (rust-lang/book#4505) ## rust-lang/reference 9 commits in b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee..cc7247d8dfaef4c39000bb12c55c32ba5b5ba976 2025-09-20 10:26:26 UTC to 2025-09-08 18:07:29 UTC - Document temporary scoping for destructuring assignments (rust-lang/reference#1992) - Specify lifetime extension of `pin!` and `format_args!` arguments (rust-lang/reference#1980) - update for more ABIs supporting c-variadics (rust-lang/reference#1936) - Fix incorrect span tag (rust-lang/reference#1995) - Remove strike attribute (rust-lang/reference#1997) - Specify the target limits for target-specific ABIs (rust-lang/reference#2000) - Remove tuple index carve out (rust-lang/reference#1966) - Enable folding of chapter listing in navigation sidebar (rust-lang/reference#1988) - Add support to grammar for single line comments (rust-lang/reference#1993) ## rust-lang/rust-by-example 1 commits in dd26bc8e726dc2e73534c8972d4dccd1bed7495f..2c9b490d70e535cf166bf17feba59e594579843f 2025-09-18 22:28:52 UTC to 2025-09-18 22:28:52 UTC - Update unit testing output for additional test (rust-lang/rust-by-example#1958)
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Pursuant to rust-lang/rust#145838 (comment), I've added a note and some examples detailing how destructuring assignment expressions effectively introduce two scopes for its temporaries, whereas basic assignment expressions don't introduce any.
I've included it alongside the description of destructuring assignment desugaring, but I could see it being at home in the destructors chapter as well. I also considered adding the assigned value operand of a destructuring assignment operand to the list of temporary scopes, but it's a bit more complicated than that since it has two scopes, so I figured it would be simplest to talk directly in terms of the desugaring, where the two scopes are visible.
I've used borrowck errors to demonstrate scoping in the tests since the test scaffolding is much simpler in that case than for testing runtime drop order, but a runtime drop order comparison may help further illustrate it.