Inner expression compilation (for match) can result in wrong line numbers

[nielsdos]

Description

The following code:

<?php
echo match(15) {
    13 => "A",
    15 => "B",
    default => "C",
};

Resulted in this output:

L0002 0000 MATCH int(15) 13: 0001, 15: 0003, default: 0005
L0003 0001 T1 = QM_ASSIGN string("A")
L0003 0002 JMP 0007
L0004 0003 T1 = QM_ASSIGN string("B")
L0004 0004 JMP 0007
L0005 0005 T1 = QM_ASSIGN string("C")
L0005 0006 JMP 0007
L0005 0007 ECHO T1    <<<<<<<<<<<<<<<<<<<<<<<< line 5 instead of 2!
L0007 0008 RETURN int(1)

But I expected this output instead:

L0002 0000 MATCH int(15) 13: 0001, 15: 0003, default: 0005
L0003 0001 T1 = QM_ASSIGN string("A")
L0003 0002 JMP 0007
L0004 0003 T1 = QM_ASSIGN string("B")
L0004 0004 JMP 0007
L0005 0005 T1 = QM_ASSIGN string("C")
L0005 0006 JMP 0007
L0002 0007 ECHO T1
L0007 0008 RETURN int(1)

The echo is on line 2, not line 5. This is because the line no gets overwritten. There's probably many more of these cases.
Discovered via krakjoe/pcov#87

Possible fix idea (may be incomplete):
https://gist.github.com/nielsdos/fe1a4b30aee84efff23f32dc4b0e5ffe

cc @iluuu1994

PHP Version

8.3+

Operating System

No response

[iluuu1994]

Your patch works for match, and it's likely one of the bigger offender because it's very common to format it over multiple lines. Hence, I would be ok with this simple patch. It does seem like this issue is not limited to match. For example, a simple binary op: https://3v4l.org/XmIih/vld#vnull

The settings of CG(zend_lineno) happens a bit all over the place. Not having thought about it too deeply, it may be possible to always reset CG(zend_lineno) at the end of zend_compile_expr(), and depend on other expressions to set lineno for themselves. If it doesn't, it will fallback to the lineno set in zend_compile_stmt(). This should be more predictable. But I haven't tried it.

[nielsdos]

I briefly explored it and it also occurs for IIFEs.

Not having thought about it too deeply, it may be possible to always reset CG(zend_lineno) at the end of zend_compile_expr()

I briefly tried this and it didn't really work but I didn't spend time on it to figure out why.