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go.tools/cmd/vet: don't complain about empty interface values in printf

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R=dsymonds
CC=golang-dev
https://golang.org/cl/12005047
This commit is contained in:
Rob Pike 2013-07-30 15:51:35 +10:00
parent 253974207b
commit 2a8b9debdd
2 changed files with 16 additions and 1 deletions
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8
cmd/vet/testdata/print.go vendored
View File

@ -88,7 +88,8 @@ func PrintfTests() {
fmt.Printf("%s", stringerarrayv) fmt.Printf("%s", stringerarrayv)
fmt.Printf("%v", notstringerarrayv) fmt.Printf("%v", notstringerarrayv)
fmt.Printf("%T", notstringerarrayv) fmt.Printf("%T", notstringerarrayv)
fmt.Printf("%*%", 2) // Ridiculous but allowed. fmt.Printf("%*%", 2) // Ridiculous but allowed.
fmt.Printf("%s", interface{}(nil)) // Nothing useful we can say.
fmt.Printf("%g", 1+2i) fmt.Printf("%g", 1+2i)
// Some bad format/argTypes // Some bad format/argTypes
@ -120,6 +121,7 @@ func PrintfTests() {
fmt.Printf("%t", stringerarrayv) // ERROR "arg stringerarrayv for printf verb %t of wrong type" fmt.Printf("%t", stringerarrayv) // ERROR "arg stringerarrayv for printf verb %t of wrong type"
fmt.Printf("%t", notstringerarrayv) // ERROR "arg notstringerarrayv for printf verb %t of wrong type" fmt.Printf("%t", notstringerarrayv) // ERROR "arg notstringerarrayv for printf verb %t of wrong type"
fmt.Printf("%q", notstringerarrayv) // ERROR "arg notstringerarrayv for printf verb %q of wrong type" fmt.Printf("%q", notstringerarrayv) // ERROR "arg notstringerarrayv for printf verb %q of wrong type"
fmt.Printf("%s", nonemptyinterface) // ERROR "for printf verb %s of wrong type"
fmt.Printf("%.*s %d %g", 3, "hi", 23, 'x') // ERROR "arg 'x' for printf verb %g of wrong type" fmt.Printf("%.*s %d %g", 3, "hi", 23, 'x') // ERROR "arg 'x' for printf verb %g of wrong type"
fmt.Println() // not an error fmt.Println() // not an error
fmt.Println("%s", "hi") // ERROR "possible formatting directive in Println call" fmt.Println("%s", "hi") // ERROR "possible formatting directive in Println call"
@ -227,3 +229,7 @@ var stringerarrayv stringerarray
type notstringerarray [4]float64 type notstringerarray [4]float64
var notstringerarrayv notstringerarray var notstringerarrayv notstringerarray
var nonemptyinterface = interface {
f()
}(nil)

9
cmd/vet/types.go
View File

@ -132,6 +132,15 @@ func (f *File) matchArgType(t printfArgType, typ types.Type, arg ast.Expr) bool
} }
return t&argPointer != 0 return t&argPointer != 0
case *types.Interface:
// If the static type of the argument is empty interface, there's little we can do.
// Example:
// func f(x interface{}) { fmt.Printf("%s", x) }
// Whether x is valid for %s depends on the type of the argument to f. One day
// we will be able to do better. For now, we assume that empty interface is OK
// but non-empty interfaces, with Stringer and Error handled above, are errors.
return typ.NumMethods() == 0
case *types.Basic: case *types.Basic:
switch typ.Kind() { switch typ.Kind() {
case types.UntypedBool, case types.UntypedBool,