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Bug 14046 – Overlapping dynamic array copy is allowed if struct contains postblit

Status: NEW
Severity: normal
Priority: P3
Component: druntime
Product: D
Version: D2
Platform: All
OS: All
Creation time: 2015-01-26T09:20:53Z
Last change time: 2024-12-07T13:34:40Z
Keywords: wrong-code
Assigned to: No Owner
Creator: Denis Shelomovskii

Comments

Comment #0 by verylonglogin.reg — 2015-01-26T09:20:53Z

Overlapping dynamic array copy is now correctly disallowed in CTFE too (Issue 11467) but in runtime this one remaining case is allowed. This code should throw `object.Error` in runtime but doesn't: --- struct S { this(this) { } } void main() { S[1] a; a[0 .. 1] = a[0 .. 1]; } ---

Comment #1 by verylonglogin.reg — 2015-01-26T09:27:43Z

The reason is in case there is no postblit `_d_arraycopy` (which enforces arrays don't overlap [1]) is called for copying and if there is a postblit `_d_arrayassign` (which allows overlapping arrays [2]) is called. [1] https://github.com/D-Programming-Language/druntime/blob/a8c74e00fe21e7781bc6d6fa1773c12b7a1e63b7/src/rt/arraycat.d#L26 [2] https://github.com/D-Programming-Language/druntime/blob/a8c74e00fe21e7781bc6d6fa1773c12b7a1e63b7/src/rt/arrayassign.d#L28

Comment #2 by robert.schadek — 2024-12-07T13:34:40Z

THIS ISSUE HAS BEEN MOVED TO GITHUB https://github.com/dlang/dmd/issues/17289 DO NOT COMMENT HERE ANYMORE, NOBODY WILL SEE IT, THIS ISSUE HAS BEEN MOVED TO GITHUB