fix: resolve receiver for binary methods on non interface types

_test/struct36.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"net/http"
+	"strings"
+)
+
+type S struct {
+	http.Client
+}
+
+func main() {
+	var s S
+	if _, err := s.Get("url"); err != nil {
+		println(strings.Contains(err.Error(), "unsupported protocol scheme"))
+	}
+	return
+}
+
+// Output:
+// true

interp/cfg.go

@@ -1219,6 +1219,7 @@ func (interp *Interpreter) cfg(root *node, pkgID string) ([]*node, error) {
 				} else {
 					n.gen = getIndexSeqMethod
 				}
+				n.recv = &receiver{node: n.child[0], index: lind}
 				n.val = append([]int{m.Index}, lind...)
 				n.typ = &itype{cat: valueT, rtype: m.Type}
 			} else if ti := n.typ.lookupField(n.child[1].ident); len(ti) > 0 {

interp/run.go

@@ -803,7 +803,7 @@ func pindex(i, variadic int) int {
 	return variadic
 }
 
-// Call a function from a bin import, accessible through reflect
+// Callbin calls a function from a bin import, accessible through reflect.
 func callBin(n *node) {
 	tnext := getExec(n.tnext)
 	fnext := getExec(n.fnext)
@@ -815,9 +815,9 @@ func callBin(n *node) {
 	if funcType.IsVariadic() {
 		variadic = funcType.NumIn() - 1
 	}
-	// method signature obtained from reflect.Type include receiver as 1st arg, except for interface types
+	// A method signature obtained from reflect.Type includes receiver as 1st arg, except for interface types.
 	rcvrOffset := 0
-	if recv := n.child[0].recv; recv != nil && recv.node.typ.TypeOf().Kind() != reflect.Interface {
+	if recv := n.child[0].recv; recv != nil && !isInterface(recv.node.typ) {
 		if funcType.NumIn() > len(child) {
 			rcvrOffset = 1
 		}

interp/type.go

@@ -871,13 +871,11 @@ func (t *itype) lookupMethod(name string) (*node, []int) {
 }
 
 // lookupBinMethod returns a method and a path to access a field in a struct object (the receiver)
-func (t *itype) lookupBinMethod(name string) (reflect.Method, []int, bool, bool) {
-	var isPtr bool
+func (t *itype) lookupBinMethod(name string) (m reflect.Method, index []int, isPtr bool, ok bool) {
 	if t.cat == ptrT {
 		return t.val.lookupBinMethod(name)
 	}
-	var index []int
-	m, ok := t.TypeOf().MethodByName(name)
+	m, ok = t.TypeOf().MethodByName(name)
 	if !ok {
 		m, ok = reflect.PtrTo(t.TypeOf()).MethodByName(name)
 		isPtr = ok