mirror of
https://github.com/golang/go
synced 2024-11-18 22:44:48 -07:00
de47ebac4b
Previously, if the result was not wanted, the received (value, ok) tuple had no type for 'value'. Now it is always set to the channel's element type. Also: set the position on such receive instructions to that of the = or := token, and document it. + (indirect) test via pointer analysis. R=crawshaw, gri CC=golang-dev https://golang.org/cl/12956052
99 lines
2.1 KiB
Go
99 lines
2.1 KiB
Go
// +build ignore
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package main
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func incr(x int) int { return x + 1 }
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func decr(x int) int { return x - 1 }
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var unknown bool // defeat dead-code elimination
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func chan1() {
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chA := make(chan func(int) int, 0) // @line c1makeA
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chB := make(chan func(int) int, 0) // @line c1makeB
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chA <- incr
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chB <- decr
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chB <- func(int) int { return 1 }
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print(chA) // @pointsto makechan@c1makeA:13
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print(<-chA) // @pointsto main.incr
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print(chB) // @pointsto makechan@c1makeB:13
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print(<-chB) // @pointsto main.decr | func@16.9
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}
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func chan2() {
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chA := make(chan func(int) int, 0) // @line c2makeA
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chB := make(chan func(int) int, 0) // @line c2makeB
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chA <- incr
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chB <- decr
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chB <- func(int) int { return 1 }
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// Channels flow together.
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// Labelsets remain distinct but elements are merged.
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chAB := chA
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if unknown {
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chAB = chB
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}
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print(chA) // @pointsto makechan@c2makeA:13
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print(<-chA) // @pointsto main.incr
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print(chB) // @pointsto makechan@c2makeB:13
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print(<-chB) // @pointsto main.decr | func@30.9
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print(chAB) // @pointsto makechan@c2makeA:13 | makechan@c2makeB:13
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print(<-chAB) // @pointsto main.incr | main.decr | func@30.9
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(<-chA)(3)
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}
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// @calls main.chan2 -> main.incr
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func chan3() {
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chA := make(chan func(int) int, 0) // @line c3makeA
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chB := make(chan func(int) int, 0) // @line c3makeB
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chA <- incr
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chB <- decr
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chB <- func(int) int { return 1 }
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print(chA) // @pointsto makechan@c3makeA:13
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print(<-chA) // @pointsto main.incr
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print(chB) // @pointsto makechan@c3makeB:13
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print(<-chB) // @pointsto main.decr | func@58.9
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(<-chA)(3)
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}
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// @calls main.chan3 -> main.incr
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func chan4() {
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chA := make(chan func(int) int, 0) // @line c4makeA
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chB := make(chan func(int) int, 0) // @line c4makeB
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select {
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case chA <- incr:
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case chB <- decr:
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case a := <-chA:
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print(a) // @pointsto main.incr
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case b := <-chB:
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print(b) // @pointsto main.decr
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default:
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print(chA) // @pointsto makechan@c4makeA:13
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print(chB) // @pointsto makechan@c4makeB:13
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}
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for k := range chA {
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print(k) // @pointsto main.incr
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}
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// Exercise constraint generation (regtest for a crash).
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for _ = range chA {
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}
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}
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func main() {
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chan1()
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chan2()
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chan3()
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chan4()
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}
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