fix: lookup embedded binary fields in struct (#207)

_test/struct18.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type AuthenticatedRequest struct {
+	http.Request
+	Username string
+}
+
+func main() {
+	a := &AuthenticatedRequest{}
+
+	fmt.Printf("%v %T\n", a.Header, a.Header)
+}
+
+// Output:
+// map[] http.Header

interp/cfg.go

@@ -1129,6 +1129,12 @@ func (interp *Interpreter) Cfg(root *Node) ([]*Node, error) {
 						n.typ = &Type{cat: ValueT, rtype: rtype}
 					}
 				}
+			} else if s, lind, ok := n.typ.lookupBinField(n.child[1].ident); ok {
+				// Handle an embedded binary field into a struct field
+				n.gen = getIndexSeqField
+				lind = append(lind, s.Index...)
+				n.val = lind
+				n.typ = &Type{cat: ValueT, rtype: s.Type}
 			} else {
 				err = n.cfgError("undefined selector: %s", n.child[1].ident)
 			}

interp/run.go

@@ -1086,6 +1086,25 @@ func getPtrIndexSeq(n *Node) {
 	}
 }
 
+func getIndexSeqField(n *Node) {
+	value := genValue(n.child[0])
+	index := n.val.([]int)
+	i := n.findex
+	next := getExec(n.tnext)
+
+	if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
+		n.exec = func(f *Frame) Builtin {
+			f.data[i] = value(f).Elem().FieldByIndex(index)
+			return next
+		}
+	} else {
+		n.exec = func(f *Frame) Builtin {
+			f.data[i] = value(f).FieldByIndex(index)
+			return next
+		}
+	}
+}
+
 func getIndexSeqMethod(n *Node) {
 	value := genValue(n.child[0])
 	index := n.val.([]int)

interp/type.go

@@ -528,6 +528,26 @@ func (t *Type) lookupField(name string) []int {
 	return nil
 }
 
+// lookupBinField returns a structfield and a path to access an embedded binary field in a struct object
+func (t *Type) lookupBinField(name string) (reflect.StructField, []int, bool) {
+	if t.cat == PtrT {
+		return t.val.lookupBinField(name)
+	}
+	var index []int
+	s, ok := t.TypeOf().FieldByName(name)
+	if !ok {
+		for i, f := range t.field {
+			if f.embed {
+				if s2, index2, ok2 := f.typ.lookupBinField(name); ok2 {
+					index = append([]int{i}, index2...)
+					return s2, index, ok2
+				}
+			}
+		}
+	}
+	return s, index, ok
+}
+
 // getMethod returns a pointer to the method definition
 func (t *Type) getMethod(name string) *Node {
 	for _, m := range t.method {