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go.tools/cmd/vet: use types.Eval to simplify some checking.

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Depends on CL 10748044

R=gri
CC=golang-dev
https://golang.org/cl/11206043
This commit is contained in:
Rob Pike 2013-07-13 07:52:00 +10:00
parent a3301d1bc6
commit b042505490
2 changed files with 18 additions and 22 deletions
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4
cmd/vet/testdata/print.go vendored
View File

@ -75,8 +75,8 @@ func PrintfTests() {
fmt.Printf("%x %x %x %x", 3, i, "hi", s)
fmt.Printf("%X %X %X %X", 3, i, "hi", s)
fmt.Printf("%.*s %d %g", 3, "hi", 23, 2.3)
fmt.Printf("%s", stringerv)
fmt.Printf("%T", stringerv)
fmt.Printf("%s", &stringerv)
fmt.Printf("%T", &stringerv)
fmt.Printf("%*%", 2) // Ridiculous but allowed.
// Some bad format/argTypes
fmt.Printf("%b", "hi") // ERROR "arg .hi. for printf verb %b of wrong type"

36
cmd/vet/types.go
View File

@ -63,31 +63,21 @@ func (pkg *Package) isStruct(c *ast.CompositeLit) (bool, string) {
}
}
var (
stringerMethodType = types.New("func() string")
errorType = types.New("interface{ Error() string }")
stringerType = types.New("interface{ String() string }")
)
func (f *File) matchArgType(t printfArgType, arg ast.Expr) bool {
// TODO: for now, we can only test builtin types, untyped constants, and Stringer/Errors.
typ := f.pkg.types[arg]
if typ == nil {
return true
}
// If we can use a string and this is a named type, does it implement the Stringer or Error interface?
// TODO: Simplify when we have the IsAssignableTo predicate in go/types.
if named, ok := typ.(*types.Named); ok && t&argString != 0 {
for i := 0; i < named.NumMethods(); i++ {
method := named.Method(i)
// Method must be either String or Error.
if method.Name() != "String" && method.Name() != "Error" {
continue
}
sig := method.Type().(*types.Signature)
// There must be zero arguments and one return.
if sig.Params().Len() != 0 || sig.Results().Len() != 1 {
continue
}
// Result must be string.
if !isUniverseString(sig.Results().At(0).Type()) {
continue
}
// It's a Stringer and we can print it.
// If we can use a string, does arg implement the Stringer or Error interface?
if t&argString != 0 {
if types.IsAssignableTo(typ, errorType) || types.IsAssignableTo(typ, stringerType) {
return true
}
}
@ -156,6 +146,12 @@ func (f *File) numArgsInSignature(call *ast.CallExpr) int {
// func Error() string
// where "string" is the universe's string type. We know the method is called "Error".
func (f *File) isErrorMethodCall(call *ast.CallExpr) bool {
typ := f.pkg.types[call]
if typ != nil {
// We know it's called "Error", so just check the function signature.
return types.IsIdentical(f.pkg.types[call.Fun], stringerMethodType)
}
// Without types, we can still check by hand.
// Is it a selector expression? Otherwise it's a function call, not a method call.
sel, ok := call.Fun.(*ast.SelectorExpr)
if !ok {
@ -166,7 +162,7 @@ func (f *File) isErrorMethodCall(call *ast.CallExpr) bool {
return false
}
// Check the type of the method declaration
typ := f.pkg.types[sel]
typ = f.pkg.types[sel]
if typ == nil {
return false
}