cmd/vet: false positives with new fmt verbs %x/%X for floating-point and complex numbers

[cespare]

I don't think vet has been updated for the new %x and %X verbs for floating-point and complex numbers.

I checked with Go 1.13 and tip. Here's a demo:

https://play.golang.org/p/-cexq-umzUo

Code:

package main

import "fmt"

func main() {
	fmt.Printf("%x\n", 1.234)
	fmt.Printf("%x\n", 1.2+3i)
	fmt.Printf("%X\n", 1.234)
	fmt.Printf("%X\n", 1.2+3i)
}

Output:

./prog.go:6:2: Printf format %x has arg 1.234 of wrong type float64
./prog.go:7:2: Printf format %x has arg 1.2 + 3i of wrong type complex128
./prog.go:8:2: Printf format %X has arg 1.234 of wrong type float64
./prog.go:9:2: Printf format %X has arg 1.2 + 3i of wrong type complex128
Go vet exited.

0x1.3be76c8b43958p+00
(0x1.3333333333333p+00+0x1.8p+01i)
0X1.3BE76C8B43958P+00
(0X1.3333333333333P+00+0X1.8P+01i)

Program exited.

[julieqiu]

/cc @alandonovan @josharian @mvdan

[cespare]

I believe the fix is trivial. I'll send a CL for x/tools and then re-vendor the copy in src/cmd after that's merged.

[gopherbot]

Change https://golang.org/cl/202041 mentions this issue: go/analysis/passes/printf: allow %x/%X for float/complex types

[gopherbot]

Change https://golang.org/cl/202083 mentions this issue: cmd/vet: re-vendor x/tools upstream for printf verb fix