Re: [go-nuts] Re: Why does this struct escape to the heap?

Yes, I came across that post when looking for info on method values and allocations. I'm sure that's the root of the problem. But I don't understand why the compiler can't figure out that no heap allocation is needed. If t doesn't escape when calling t.M(), why can't the compiler work out

Re: [go-nuts] Re: Why does this struct escape to the heap?

Perhaps... https://groups.google.com/forum/m/#!topic/golang-nuts/aMicHmoOH1c On Thu, 6 Sep 2018, 17:26 , wrote: > Using a pointer receiver (as in your noEscape example) just pushes the > problem up the stack. When you try to call it, e.g. > > > func parent() bool { > var opts options >

Re: [go-nuts] Re: Why does this struct escape to the heap?

Using a pointer receiver (as in your noEscape example) just pushes the problem up the stack. When you try to call it, e.g. func parent() bool { var opts options return noEscape('0', ) } you find that escapes to the heap in the parent function instead. I haven't opened an issue yet

Re: [go-nuts] Re: Why does this struct escape to the heap?

I think this has to do with the pointer reciever, vs the pass by value: func noEscape(r rune, opts *options) bool { f := opts.isDigit return f(r) } opts here does not escape, but in: func escapes(r rune, opts options) bool { f := opts.isDigit return f(r) } opts is copied, so it is the

[go-nuts] Re: Why does this struct escape to the heap?

I wonder if this is to do with method values. According to the spec , when you declare a method value like x.M: The expression x is evaluated and saved during the evaluation of the method > value; the saved copy is then used as the receiver in any

Re: [go-nuts] Re: Why does this struct escape to the heap?

Hi Paul, Perhaps my answer was a bit simplistic, and I admit that I answered without looking too much into it. Basically, in your index1, the opts.isDigit passed to IndexFunc is > syntactic sugar for ().isDigit -> then the compiler needs to move opts > on the heap. "*Why? Taking a reference to

[go-nuts] Re: Why does this struct escape to the heap?

FYI, here is the escape analysis output. $ go build -gcflags="-l -m=2" ./escape.go:20:10: capturing by ref: opts (addr=true assign=false width= 4) ./escape.go:9:38: (*options).isDigit opts does not escape ./escape.go:15:34: opts escapes to heap ./escape.go:15:34: from opts.isDigit (call

[go-nuts] Re: Why does this struct escape to the heap?

Hi Silviu, Thanks for your reply. I'm not sure about the points you raise though. Basically, in your index1, the opts.isDigit passed to IndexFunc is > syntactic sugar for ().isDigit -> then the compiler needs to move opts > on the heap. Why? Taking a reference to a function argument

[go-nuts] Re: Why does this struct escape to the heap?

Hi Paul, Check out: https://golang.org/doc/effective_go.html#pointers_vs_values Basically, in your index1, the opts.isDigit passed to IndexFunc is syntactic sugar for ().isDigit -> then the compiler needs to move opts on the heap. You can either a) define an alternate isDigitVal method,