Bug 20365 – Copy constructor not invoked on static arrays of structs but the postblit works

Copy constructor case: https://run.dlang.io/is/xzVWOi ``` extern(C) void puts(const char*); struct S { long[3] a; this(ref typeof(this)) { puts("CC"); } } void main() { S[4] a; auto b = a; } ``` Prints nothing. Expected to print "CC" four times. Postblit case: https://run.dlang.io/is/OX4O8I ``` extern(C) void puts(const char*); struct S { long[3] a; this(this) { puts("PB"); } } void main() { S[4] a; auto b = a; } ``` prints "PB" four times as expected.

Let's include CatAssign as well for completeness: S[] c; c ~= a; // no copy ctor calls, but 4 postblits

There is a whole jungle of pustblit calls in druntime that do not call the copy constructor yet. Just grep the word "postblit" in druntime source to get an idea. I contacted Razvan about it.

This can be nicely solved with the new hasCopyConstructor/hasPostblit traits [1]. I will look into it. [1] https://github.com/dlang/dmd/pull/10528

*** Issue 21368 has been marked as a duplicate of this issue. ***

(In reply to kinke from comment #1) > Let's include CatAssign as well for completeness: > > S[] c; > c ~= a; // no copy ctor calls, but 4 postblits The CatAssign example seems to have been fixed, but the initial assign example still fails.

@RazvanN7 created dlang/dmd pull request #14372 "Fix Issue 20365 - Copy constructor not invoked on static arrays of structs but the postblit works" fixing this issue: - Fix Issue 20365 - Copy constructor not invoked on static arrays of structs but the postblit works https://github.com/dlang/dmd/pull/14372