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| author | Clyybber <darkmine956@gmail.com> | 2021-01-20 11:05:56 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-01-20 11:05:56 +0100 |
| commit | ccb11a63fb7bf4cf44a23e1b42334fd4c0664422 (patch) | |
| tree | 47c2ab350baa2323cf2d44a0aef765f02048110c /doc/destructors.rst | |
| parent | 4fc7fcb775140dc774a713063917fbf7d1392bdf (diff) | |
| download | Nim-ccb11a63fb7bf4cf44a23e1b42334fd4c0664422.tar.gz | |
Reboot of #16195 (#16746)
* fix #16185 * fix test * fix comment * fix comment * better approach * Add more tests and move sameLocation to injectdestructors * Better and more strict sameLocation * Small cleanup and preliminary spec clarification * Fix * Fix doc * Expand test Co-authored-by: Andrey R (cooldome) <ariabushenko@gmail.com>
Diffstat (limited to 'doc/destructors.rst')
| -rw-r--r-- | doc/destructors.rst | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/doc/destructors.rst b/doc/destructors.rst index e48e360dd..c3a7e7744 100644 --- a/doc/destructors.rst +++ b/doc/destructors.rst @@ -376,8 +376,14 @@ it's subtle. The simple case of ``x = x`` cannot be turned into ``=sink(x, x); wasMoved(x)`` because that would lose ``x``'s value. -The solution is that simple self-assignments are simply transformed into -an empty statement that does nothing. +The solution is that simple self-assignments that consist of + +- Symbols: ``x = x`` +- Field access: ``x.f = x.f`` +- Array, sequence or string access with indices known at compile-time: ``x[0] = x[0]`` + +are transformed into an empty statement that does nothing. +The compiler is free to optimize further cases. The complex case looks like a variant of ``x = f(x)``, we consider ``x = select(rand() < 0.5, x, y)`` here: |