Checking for methodset existance

interp/interpreter.go

@@ -427,9 +427,20 @@ func (r *runner) run(fn *function, params []value, parentMem *memoryView, indent
  if err != nil {
  return nil, mem, r.errorAt(inst, err)
  }
+ // typecodePtr always point to the numMethod field in the type
+ // description struct. The methodSet, when present, comes right
+ // before the numMethod field (the compiler doesn't generate
+ // method sets for concrete types without methods).
+ // Considering that the compiler doesn't emit interface type
+ // asserts for interfaces with no methods (as the always succeed)
+ // then if the offset is zero, this assert must always fail.
+ if typecodePtr.offset() == 0 {
+ locals[inst.localIndex] = literalValue{uint8(0)}
+ break
+ }
  typecodePtrOffset, err := typecodePtr.addOffset(-int64(r.pointerSize))
  if err != nil {
- return nil, mem, r.errorAt(inst, err) // unlikely
+ return nil, mem, r.errorAt(inst, err)
  }
  methodSetPtr, err := mem.load(typecodePtrOffset, r.pointerSize).asPointer(r)
  if err != nil {

testdata/init.go

@@ -109,3 +109,14 @@ func sliceString(s string, start, end int) string {
 func sliceSlice(s []int, start, end int) []int {
  return s[start:end]
 }
+
+type outside struct{}
+
+func init() {
+ _, _ = any(0).(interface{ DoesNotExist() })
+ _, _ = any("").(interface{ DoesNotExist() })
+ _, _ = any(outside{}).(interface{ DoesNotExist() })
+
+ type inside struct{}
+ _, _ = any(inside{}).(interface{ DoesNotExist() })
+}