if v1.Len() != v2.Len() {
			return false
		}
		if v1.UnsafePointer() == v2.UnsafePointer() {
			return true
		}
		iter := v1.MapRange()
		for iter.Next() {
			val1 := iter.Value()
			val2 := v2.MapIndex(iter.Key())
			if !val1.IsValid() || !val2.IsValid() || !deepValueEqual(val1, val2, visited) {
				return false
			}
		}
		return true
	case Func:
		if v1.IsNil() && v2.IsNil() {
			return true
		}

	case reflect.Map:
		p.printf("%s (len = %d) {", x.Type(), x.Len())
		if x.Len() > 0 {
			p.indent++
			p.printf("\n")
			for _, key := range x.MapKeys() {
				p.print(key)
				p.printf(": ")
				p.print(x.MapIndex(key))
				p.printf("\n")
			}
			p.indent--
		}
		p.printf("}")

	case reflect.Pointer:
		p.printf("*")
		// type-checked ASTs may contain cycles - use ptrmap

	case tv.IsType():
		return "type"
	case tv.IsBuiltin():
		return "builtin"
	case tv.IsNil():
		return "nil"
	case tv.Assignable():
		if tv.Addressable() {
			return "var"
		}
		return "mapindex"
	case tv.IsValue():
		return "value"
	default:
		return "unknown"
	}
}

func exprString(fset *token.FileSet, expr ast.Expr) string {
	var buf strings.Builder
	format.Node(&buf, fset, expr)