Thanks for the confirmation, I created https://github.com/golang/go/issues/71054 for this.
On Saturday, December 28, 2024 at 6:11:52 PM UTC-8 Ian Lance Taylor wrote: > On Sat, Dec 28, 2024 at 5:38 PM Kaiming Yang <yax...@gmail.com> wrote: > > > > I'm trying to understand execution order of assignment statement, as > spec mentioned: > > > > > The assignment proceeds in two phases. First, the operands of index > expressions and pointer indirections (including implicit pointer > indirections in selectors) on the left and the expressions on the right are > all evaluated in the usual order. Second, the assignments are carried out > in left-to-right order. > > > > I crafted a example about it: https://go.dev/play/p/6RulNQwIk4n, the > core of that example is this line: > > > > phase_2, foo.bar.value = "??????", compute_value() > > > > where `foo.bar.value` causes panic due to nil pointer. > > > > The execution result shows `compute_value()` is invoked, but `phase_2` > variable is not updated. Seems like the panic happened after phase 1 is > complete but before phase 2 started. > > > > I assume the panic should happen in one of two phases, but not > in-between. If panic happened in phase 1, `compute_value()` should not be > invoked due to it happen later in same phase; If panic happened in phase 2, > `phase_2` variable should have been changed already. > > > > Is the behavior working-as-indented? if so, what am I missing to > understand it? > > Thanks. This looks like a bug to me. I think the panic should occur > before compute_value is called. When I run your program with gccgo I > get > > original > panic: runtime error: invalid memory address or nil pointer dereference > [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x4037fb] > > goroutine 1 [running]: > main.main > foo.go:22 > > Want to open a bug report at https://go.dev/issue? Thanks. > > Ian > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/golang-nuts/86992c12-4510-4008-abc4-2a795e26c3b8n%40googlegroups.com.
