func (p *exporter) field(f *types.Var) {
// anonymous fields have "" name
name := ""
if !f.Anonymous() {
name = f.Name()
}
// qualifiedName will always emit the field package for
// anonymous fields because "" is not an exported name.
p.qualifiedName(f.Pkg(), name)
p.typ(f.Type())
}
// fieldName is like qualifiedName but it doesn't record the package
// for blank (_) or exported names.
func (p *exporter) fieldName(f *types.Var) {
name := f.Name()
// anonymous field with unexported base type name: use "?" as field name
// (bname != "" per spec, but we are conservative in case of errors)
if f.Anonymous() {
base := f.Type()
if ptr, ok := base.(*types.Pointer); ok {
base = ptr.Elem()
}
if named, ok := base.(*types.Named); ok && !named.Obj().Exported() {
name = "?"
}
}
p.string(name)
if name == "?" || name != "_" && !f.Exported() {
p.pkg(f.Pkg(), false)
}
}
// checkStructField checks that the field renaming will not cause
// conflicts at its declaration, or ambiguity or changes to any selection.
func (r *renamer) checkStructField(from *types.Var) {
// Check that the struct declaration is free of field conflicts,
// and field/method conflicts.
// go/types offers no easy way to get from a field (or interface
// method) to its declaring struct (or interface), so we must
// ascend the AST.
info, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
// path matches this pattern:
// [Ident SelectorExpr? StarExpr? Field FieldList StructType ParenExpr* ... File]
// Ascend to FieldList.
var i int
for {
if _, ok := path[i].(*ast.FieldList); ok {
break
}
i++
}
i++
tStruct := path[i].(*ast.StructType)
i++
// Ascend past parens (unlikely).
for {
_, ok := path[i].(*ast.ParenExpr)
if !ok {
break
}
i++
}
if spec, ok := path[i].(*ast.TypeSpec); ok {
// This struct is also a named type.
// We must check for direct (non-promoted) field/field
// and method/field conflicts.
named := info.Defs[spec.Name].Type()
prev, indices, _ := types.LookupFieldOrMethod(named, true, info.Pkg, r.to)
if len(indices) == 1 {
r.errorf(from.Pos(), "renaming this field %q to %q",
from.Name(), r.to)
r.errorf(prev.Pos(), "\twould conflict with this %s",
objectKind(prev))
return // skip checkSelections to avoid redundant errors
}
} else {
// This struct is not a named type.
// We need only check for direct (non-promoted) field/field conflicts.
T := info.Types[tStruct].Type.Underlying().(*types.Struct)
for i := 0; i < T.NumFields(); i++ {
if prev := T.Field(i); prev.Name() == r.to {
r.errorf(from.Pos(), "renaming this field %q to %q",
from.Name(), r.to)
r.errorf(prev.Pos(), "\twould conflict with this field")
return // skip checkSelections to avoid redundant errors
}
}
}
// Renaming an anonymous field requires renaming the type too. e.g.
// print(s.T) // if we rename T to U,
// type T int // this and
// var s struct {T} // this must change too.
if from.Anonymous() {
if named, ok := from.Type().(*types.Named); ok {
r.check(named.Obj())
} else if named, ok := deref(from.Type()).(*types.Named); ok {
r.check(named.Obj())
}
}
// Check integrity of existing (field and method) selections.
r.checkSelections(from)
}