--- a/src/eval.c
+++ b/src/eval.c
@@ -1050,11 +1050,14 @@ flag_string_T glv_flag_strings[] = {
  *	execute_instructions: ISN_LOCKUNLOCK - sets lval_root from stack.
  */
     static void
-get_lval_root(lval_T *lp, lval_root_T *lr)
+fill_lval_from_lval_root(lval_T *lp, lval_root_T *lr)
 {
 #ifdef LOG_LOCKVAR
-    ch_log(NULL, "LKVAR: get_lval_root(): name %s", lp->ll_name);
+    ch_log(NULL, "LKVAR: fill_lval_from_lval_root(): name %s, tv %p",
+						lp->ll_name, (void*)lr->lr_tv);
 #endif
+    if (lr->lr_tv == NULL)
+	return;
     if (!lr->lr_is_arg && lr->lr_tv->v_type == VAR_CLASS)
     {
 	if (lr->lr_tv->vval.v_class != NULL)
@@ -1177,15 +1180,14 @@ get_lval(
 
 #ifdef LOG_LOCKVAR
     if (lval_root == NULL)
-	ch_log(NULL,
-	       "LKVAR: get_lval(): name %s, lval_root (nil)", name);
+	ch_log(NULL, "LKVAR: get_lval(): name: %s, lval_root (nil)", name);
     else
-	ch_log(NULL,
-	   "LKVAR: get_lval(): name %s, lr_tv %p lr_is_arg %d",
-	    name, (void*)lval_root->lr_tv, lval_root->lr_is_arg);
+	ch_log(NULL, "LKVAR: get_lval(): name: %s, lr_tv %p lr_is_arg %d",
+			name, (void*)lval_root->lr_tv, lval_root->lr_is_arg);
     char buf[80];
-    ch_log(NULL, "LKVAR:    ...: GLV flags %s",
+    ch_log(NULL, "LKVAR:    ...: GLV flags: %s",
 		    flags_tostring(flags, glv_flag_strings, buf, sizeof(buf)));
+    int log_sync_root_key = FALSE;
 #endif
 
     // Clear everything in "lp".
@@ -1324,20 +1326,26 @@ get_lval(
 	}
     }
 
-    // Without [idx] or .key we are done.
-    if ((*p != '[' && *p != '.'))
+    int sync_root = FALSE;
+    if (vim9script && lval_root != NULL)
+    {
+	cl_exec = lval_root->lr_cl_exec;
+	sync_root = lval_root->lr_sync_root;
+    }
+
+    // Without [idx] or .key we are done, unless doing sync_root.
+    if (*p != '[' && *p != '.' && (*name == NUL || !sync_root))
     {
 	if (lval_root != NULL)
-	    get_lval_root(lp, lval_root);
+	    fill_lval_from_lval_root(lp, lval_root);
 	return p;
     }
 
-    if (vim9script && lval_root != NULL)
+    if (vim9script && lval_root != NULL && lval_root->lr_tv != NULL)
     {
 	// using local variable
 	lp->ll_tv = lval_root->lr_tv;
 	v = NULL;
-	cl_exec = lval_root->lr_cl_exec;
     }
     else
     {
@@ -1367,7 +1375,7 @@ get_lval(
      */
     var1.v_type = VAR_UNKNOWN;
     var2.v_type = VAR_UNKNOWN;
-    while (*p == '[' || (*p == '.' && p[1] != '=' && p[1] != '.'))
+    while (*p == '[' || (*p == '.' && p[1] != '=' && p[1] != '.') || sync_root)
     {
 	vartype_T v_type = lp->ll_tv->v_type;
 
@@ -1407,6 +1415,10 @@ get_lval(
 		emsg(_(e_slice_must_come_last));
 	    return NULL;
 	}
+#ifdef LOG_LOCKVAR
+	ch_log(NULL, "LKVAR: get_lval() loop: p: %s, type: %s", p,
+							vartype_name(v_type));
+#endif
 
 	if (vim9script && lp->ll_valtype == NULL
 		&& v != NULL
@@ -1417,11 +1429,29 @@ get_lval(
 
 	    // Vim9 script local variable: get the type
 	    if (sv != NULL)
+	    {
 		lp->ll_valtype = sv->sv_type;
+#ifdef LOG_LOCKVAR
+		ch_log(NULL, "LKVAR:    ... loop: vim9 assign type: %s",
+					vartype_name(lp->ll_valtype->tt_type));
+#endif
+	    }
 	}
 
 	len = -1;
-	if (*p == '.')
+	if (sync_root)
+	{
+	    // For example, the first token is a member variable name and
+	    // lp->ll_tv is a class/object.
+	    // Process it directly without looking for "[idx]" or ".name".
+	    key = name;
+	    sync_root = FALSE;  // only first time through
+#ifdef LOG_LOCKVAR
+	    log_sync_root_key = TRUE;
+	    ch_log(NULL, "LKVAR:    ... loop: name: %s, sync_root", name);
+#endif
+	}
+	else if (*p == '.')
 	{
 	    key = p + 1;
 	    for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
@@ -1512,6 +1542,17 @@ get_lval(
 	    // Skip to past ']'.
 	    ++p;
 	}
+#ifdef LOG_LOCKVAR
+	if (log_sync_root_key)
+	    ch_log(NULL, "LKVAR:    ... loop: p: %s, sync_root key: %s", p,
+									key);
+	else if (len == -1)
+	    ch_log(NULL, "LKVAR:    ... loop: p: %s, '[' key: %s", p,
+				empty1 ? ":" : (char*)tv_get_string(&var1));
+	else
+	    ch_log(NULL, "LKVAR:    ... loop: p: %s, '.' key: %s", p, key);
+	log_sync_root_key = FALSE;
+#endif
 
 	if (v_type == VAR_DICT)
 	{
@@ -1700,8 +1741,14 @@ get_lval(
 	    lp->ll_list = NULL;
 
 	    class_T *cl;
-	    if (v_type == VAR_OBJECT && lp->ll_tv->vval.v_object != NULL)
+	    if (v_type == VAR_OBJECT)
 	    {
+		if (lp->ll_tv->vval.v_object == NULL)
+		{
+		    if (!quiet)
+			emsg(_(e_using_null_object));
+		    return NULL;
+		}
 	        cl = lp->ll_tv->vval.v_object->obj_class;
 	        lp->ll_object = lp->ll_tv->vval.v_object;
 	    }

--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -7308,6 +7308,83 @@ f_invert(typval_T *argvars, typval_T *re
 }
 
 /*
+ * Free resources in lval_root allocated by fill_exec_lval_root().
+ */
+    static void
+free_lval_root(lval_root_T *root)
+{
+    if (root->lr_tv != NULL)
+	free_tv(root->lr_tv);
+    class_unref(root->lr_cl_exec);
+    root->lr_tv = NULL;
+    root->lr_cl_exec = NULL;
+}
+
+/*
+ * This is used if executing in a method, the argument string is a
+ * variable/item expr/reference. If it starts with a potential class/object
+ * variable then return OK, may get later errors in get_lval.
+ *
+ * Adjust "root" as needed. Note that name may change (for example to skip
+ * "this") and is returned. lr_tv may be changed or freed.
+ *
+ * Always returns OK.
+ * Free resources and return FAIL if the root should not be used. Otherwise OK.
+ */
+
+    static int
+fix_variable_reference_lval_root(lval_root_T *root, char_u **p_name)
+{
+    char_u	*name = *p_name;
+    char_u	*end;
+    dictitem_T	*di;
+
+    // Only set lr_sync_root and lr_tv if the name is an object/class
+    // reference: object ("this.") or class because name is class variable.
+    if (root->lr_tv->v_type == VAR_OBJECT)
+    {
+	if (STRNCMP("this.", name, 5) == 0)
+	{
+	    name += 5;
+	        root->lr_sync_root = TRUE;
+	}
+	else if (STRCMP("this", name) == 0)
+	{
+	    name += 4;
+	    root->lr_sync_root = TRUE;
+	}
+    }
+    if (!root->lr_sync_root)	// not object member, try class member
+    {
+	// Explicitly check if the name is a class member.
+	// If it's not then do nothing.
+	for (end = name; ASCII_ISALNUM(*end) || *end == '_'; ++end)
+	    ;
+	if (class_member_lookup(root->lr_cl_exec, name, end - name, NULL)
+								    != NULL)
+	{
+	    // Using a class, so reference the class tv.
+	    di = find_var(root->lr_cl_exec->class_name, NULL, FALSE);
+	    if (di != NULL)
+	    {
+		// replace the lr_tv
+		clear_tv(root->lr_tv);
+		copy_tv(&di->di_tv, root->lr_tv);
+		root->lr_sync_root = TRUE;
+	    }
+	}
+    }
+    if (!root->lr_sync_root)
+    {
+	free_tv(root->lr_tv);
+	root->lr_tv = NULL;	    // Not a member variable
+    }
+    *p_name = name;
+    // If FAIL, then must free_lval_root(root);
+    return OK;
+}
+
+/*
  * "islocked()" function
  */
     static void
@@ -7322,9 +7399,34 @@ f_islocked(typval_T *argvars, typval_T *
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
 	return;
 
-    end = get_lval(tv_get_string(&argvars[0]), NULL, &lv, FALSE, FALSE,
+    char_u *name = tv_get_string(&argvars[0]);
+#ifdef LOG_LOCKVAR
+    ch_log(NULL, "LKVAR: f_islocked(): name: %s", name);
+#endif
+
+    lval_root_T	aroot;	// fully initialized in fill_exec_lval_root
+    lval_root_T *root = NULL;
+
+    // Set up lval_root if executing in a method.
+    if (fill_exec_lval_root(&aroot) == OK)
+    {
+	// Almost always produces a valid lval_root since lr_cl_exec is used
+	// for access verification, lr_tv may be set to NULL.
+	char_u *tname = name;
+	if (fix_variable_reference_lval_root(&aroot, &tname) == OK)
+	{
+	    name = tname;
+	    root = &aroot;
+	}
+    }
+
+    lval_root_T	*lval_root_save = lval_root;
+    lval_root = root;
+    end = get_lval(name, NULL, &lv, FALSE, FALSE,
 			     GLV_NO_AUTOLOAD | GLV_READ_ONLY | GLV_NO_DECL,
 			     FNE_CHECK_START);
+    lval_root = lval_root_save;
+
     if (end != NULL && lv.ll_name != NULL)
     {
 	if (*end != NUL)
@@ -7347,6 +7449,10 @@ f_islocked(typval_T *argvars, typval_T *
 						   || tv_islocked(&di->di_tv));
 		}
 	    }
+	    else if (lv.ll_is_root)
+	    {
+		rettv->vval.v_number = tv_islocked(lv.ll_tv);
+	    }
 	    else if (lv.ll_object != NULL)
 	    {
 		typval_T *tv = ((typval_T *)(lv.ll_object + 1)) + lv.ll_oi;
@@ -7376,6 +7482,8 @@ f_islocked(typval_T *argvars, typval_T *
 	}
     }
 
+    if (root != NULL)
+	free_lval_root(root);
     clear_lval(&lv);
 }
 

--- a/src/proto/vim9execute.pro
+++ b/src/proto/vim9execute.pro
@@ -4,6 +4,7 @@ void update_has_breakpoint(ufunc_T *ufun
 int funcstack_check_refcount(funcstack_T *funcstack);
 int set_ref_in_funcstacks(int copyID);
 int in_def_function(void);
+int fill_exec_lval_root(lval_root_T *lr);
 ectx_T *clear_current_ectx(void);
 void restore_current_ectx(ectx_T *ectx);
 int add_defer_function(char_u *name, int argcount, typval_T *argvars);

--- a/src/structs.h
+++ b/src/structs.h
@@ -4604,13 +4604,16 @@ typedef struct lval_S
 } lval_T;
 
 /**
- * This may be used to specify the base type that get_lval() uses when
+ * This may be used to specify the base typval that get_lval() uses when
  * following a chain, for example a[idx1][idx2].
+ * The lr_sync_root flags signals get_lval that the first time through
+ * the indexing loop, skip handling  '.' and '[idx]'.
  */
 typedef struct lval_root_S {
     typval_T	*lr_tv;
     class_T	*lr_cl_exec;	// executing class for access checking
     int		lr_is_arg;
+    int		lr_sync_root;
 } lval_root_T;
 
 // Structure used to save the current state.  Used when executing Normal mode

--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -1704,8 +1704,7 @@ def Test_class_member()
     var obj: A
     obj.val = ""
   END
-  # FIXME(in source): this should give E1360 as well!
-  v9.CheckSourceFailure(lines, 'E1012: Type mismatch; expected object<A> but got string', 7)
+  v9.CheckSourceFailure(lines, 'E1360: Using a null object', 7)
 
   # Test for accessing a member on a null object, at script level
   lines =<< trim END
@@ -4259,8 +4258,249 @@ def Test_lockvar_islocked()
     assert_equal(0, islocked("C.c1[0]"))
   END
   v9.CheckSourceSuccess(lines)
-  lines =<< trim END
-  END
+
+  # Do islocked() from an object method
+  # and then from a class method
+  lines =<< trim END
+    vim9script
+
+    var l0o0 = [  [0],   [1],   [2]]
+    var l0o1 = [ [10],  [11],  [12]]
+    var l0c0 = [[120], [121], [122]]
+    var l0c1 = [[130], [131], [132]]
+
+    class C0
+      this.o0: list<list<number>> =   l0o0
+      this.o1: list<list<number>> =   l0o1
+      static c0: list<list<number>> = l0c0
+      static c1: list<list<number>> = l0c1
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+      static def SIslocked(arg: string): number
+        return islocked(arg)
+      enddef
+    endclass
+
+    var l2o0 = [[20000], [20001], [20002]]
+    var l2o1 = [[20010], [20011], [20012]]
+    var l2c0 = [[20120], [20121], [20122]]
+    var l2c1 = [[20130], [20131], [20132]]
+
+    class C2
+      this.o0: list<list<number>> =   l2o0
+      this.o1: list<list<number>> =   l2o1
+      static c0: list<list<number>> = l2c0
+      static c1: list<list<number>> = l2c1
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+      static def SIslocked(arg: string): number
+        return islocked(arg)
+      enddef
+    endclass
+
+    var obj0 = C0.new()
+    var obj2 = C2.new()
+
+    var l = [ obj0, null_object, obj2 ]
+
+    # lock list, object func access through script var expr
+    assert_equal(0, obj0.Islocked("l[0].o0"))
+    assert_equal(0, obj0.Islocked("l[0].o0[2]"))
+    lockvar l0o0
+    assert_equal(1, obj0.Islocked("l[0].o0"))
+    assert_equal(1, obj0.Islocked("l[0].o0[2]"))
+
+    #echo "check-b" obj2.Islocked("l[1].o1")    # NULL OBJECT
+
+    # lock list element, object func access through script var expr
+    lockvar l0o1[1]
+    assert_equal(0, obj0.Islocked("this.o1[0]"))
+    assert_equal(1, obj0.Islocked("this.o1[1]"))
+
+    assert_equal(0, obj0.Islocked("this.o1"))
+    lockvar l0o1
+    assert_equal(1, obj0.Islocked("this.o1"))
+    unlockvar l0o1
+
+    lockvar l0c1[1]
+
+    # static by class name member expr from same class
+    assert_equal(0, obj0.Islocked("C0.c1[0]"))
+    assert_equal(1, obj0.Islocked("C0.c1[1]"))
+    # static by bare name member expr from same class
+    assert_equal(0, obj0.Islocked("c1[0]"))
+    assert_equal(1, obj0.Islocked("c1[1]"))
+
+    # static by class name member expr from other class
+    assert_equal(0, obj2.Islocked("C0.c1[0]"))
+    assert_equal(1, obj2.Islocked("C0.c1[1]"))
+    # static by bare name member expr from other class
+    assert_equal(0, obj2.Islocked("c1[0]"))
+    assert_equal(0, obj2.Islocked("c1[1]"))
+
+
+    # static by bare name in same class
+    assert_equal(0, obj0.Islocked("c0"))
+    lockvar l0c0
+    assert_equal(1, obj0.Islocked("c0"))
+
+    #
+    # similar stuff, but use static method
+    #
+
+    unlockvar l0o0
+
+    # lock list, object func access through script var expr
+    assert_equal(0, C0.SIslocked("l[0].o0"))
+    assert_equal(0, C0.SIslocked("l[0].o0[2]"))
+    lockvar l0o0
+    assert_equal(1, C0.SIslocked("l[0].o0"))
+    assert_equal(1, C0.SIslocked("l[0].o0[2]"))
+
+    unlockvar l0o1
+
+    # can't access "this" from class method
+    try
+      C0.SIslocked("this.o1[0]")
+      call assert_0(1, '"C0.SIslocked("this.o1[0]")" should have failed')
+    catch
+      call assert_exception('E121: Undefined variable: this')
+    endtry
+
+    lockvar l0c1[1]
+
+    # static by class name member expr from same class
+    assert_equal(0, C0.SIslocked("C0.c1[0]"))
+    assert_equal(1, C0.SIslocked("C0.c1[1]"))
+    # static by bare name member expr from same class
+    assert_equal(0, C0.SIslocked("c1[0]"))
+    assert_equal(1, C0.SIslocked("c1[1]"))
+
+    # static by class name member expr from other class
+    assert_equal(0, C2.SIslocked("C0.c1[0]"))
+    assert_equal(1, C2.SIslocked("C0.c1[1]"))
+    # static by bare name member expr from other class
+    assert_equal(0, C2.SIslocked("c1[0]"))
+    assert_equal(0, C2.SIslocked("c1[1]"))
+
+
+    # static by bare name in same class
+    unlockvar l0c0
+    assert_equal(0, C0.SIslocked("c0"))
+    lockvar l0c0
+    assert_equal(1, C0.SIslocked("c0"))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  # Check islocked class/object from various places.
+  lines =<< trim END
+    vim9script
+
+    class C
+      def Islocked(arg: string): number
+        return islocked(arg)
+      enddef
+      static def SIslocked(arg: string): number
+        return islocked(arg)
+      enddef
+    endclass
+    var obj = C.new()
+
+    # object method
+    assert_equal(0, obj.Islocked("this"))
+    assert_equal(0, obj.Islocked("C"))
+
+    # class method
+    ### assert_equal(0, C.SIslocked("this"))
+    assert_equal(0, C.SIslocked("C"))
+
+    #script level
+    var v: number
+    v = islocked("C")
+    assert_equal(0, v)
+    v = islocked("obj")
+    assert_equal(0, v)
+  END
+  v9.CheckSourceSuccess(lines)
+enddef
+
+def Test_lockvar_islocked_notfound()
+  # Try non-existent things
+  var lines =<< trim END
+    vim9script
+
+    class C
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+      static def SIslocked(arg: string): number
+        return islocked(arg)
+      enddef
+    endclass
+    var obj = C.new()
+    assert_equal(-1, obj.Islocked("anywhere"))
+    assert_equal(-1, C.SIslocked("notanywhere"))
+  END
+  v9.CheckSourceSuccess(lines)
+
+  # Something not found of the form "name1.name2" is an error
+  lines =<< trim END
+    vim9script
+
+    islocked("one.two")
+  END
+  v9.CheckSourceFailure(lines, 'E121: Undefined variable: one')
+
+  lines =<< trim END
+    vim9script
+
+    class C
+      this.val = { key: "value" }
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+    endclass
+    var obj = C.new()
+    obj.Islocked("this.val.not_there"))
+  END
+  v9.CheckSourceFailure(lines, 'E716: Key not present in Dictionary: "not_there"')
+
+  lines =<< trim END
+    vim9script
+
+    class C
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+    endclass
+    var obj = C.new()
+    obj.Islocked("this.notobjmember")
+  END
+  v9.CheckSourceFailure(lines, 'E1326: Variable not found on object "C": notobjmember')
+
+  # access a script variable through methods
+  lines =<< trim END
+    vim9script
+
+    var l = [1]
+    class C
+      def Islocked(arg: string): number
+          return islocked(arg)
+      enddef
+      static def SIslocked(arg: string): number
+        return islocked(arg)
+      enddef
+    endclass
+    var obj = C.new()
+    assert_equal(0, obj.Islocked("l"))
+    assert_equal(0, C.SIslocked("l"))
+    lockvar l
+    assert_equal(1, obj.Islocked("l"))
+    assert_equal(1, C.SIslocked("l"))
+  END
+  v9.CheckSourceSuccess(lines)
 enddef
 
 " Test for a private object method

--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2015,
+/**/
     2014,
 /**/
     2013,

--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -926,6 +926,41 @@ in_def_function(void)
 }
 
 /*
+ * If executing a class/object method, then fill in the lval_T.
+ * Set lr_tv to the executing item, and lr_exec_class to the executing class;
+ * use free_tv and class_unref when finished with the lval_root.
+ * For use by builtin functions.
+ *
+ * Return FAIL and do nothing if not executing in a class; otherwise OK.
+ */
+    int
+fill_exec_lval_root(lval_root_T *root)
+{
+    ectx_T *ectx = current_ectx;
+    if (ectx != NULL)
+    {
+	dfunc_T	    *dfunc = ((dfunc_T *)def_functions.ga_data)
+						  + current_ectx->ec_dfunc_idx;
+	ufunc_T    *ufunc = dfunc->df_ufunc;
+	if (ufunc->uf_class != NULL)	// executing a method?
+	{
+	    typval_T *tv = alloc_tv();
+	    if (tv != NULL)
+	    {
+		CLEAR_POINTER(root);
+		root->lr_tv = tv;
+		copy_tv(STACK_TV_VAR(0), root->lr_tv);
+		root->lr_cl_exec = ufunc->uf_class;
+		++root->lr_cl_exec->class_refcount;
+		return OK;
+	    }
+	}
+    }
+
+    return FAIL;
+}
+
+/*
  * Clear "current_ectx" and return the previous value.  To be used when calling
  * a user function.
  */
@@ -4185,21 +4220,20 @@ exec_instructions(ectx_T *ectx)
 
 	    case ISN_LOCKUNLOCK:
 		{
-		    lval_root_T	*lval_root_save = lval_root;
-		    int		res;
 #ifdef LOG_LOCKVAR
 		    ch_log(NULL, "LKVAR: execute INS_LOCKUNLOCK isn_arg %s",
 							iptr->isn_arg.string);
 #endif
+		    lval_root_T	*lval_root_save = lval_root;
 
 		    // Stack has the local variable, argument the whole :lock
 		    // or :unlock command, like ISN_EXEC.
 		    --ectx->ec_stack.ga_len;
-		    lval_root_T root = { STACK_TV_BOT(0),
-					iptr->isn_arg.lockunlock.lu_cl_exec,
-					iptr->isn_arg.lockunlock.lu_is_arg };
+		    lval_root_T root = { .lr_tv = STACK_TV_BOT(0),
+			    .lr_cl_exec = iptr->isn_arg.lockunlock.lu_cl_exec,
+			    .lr_is_arg  = iptr->isn_arg.lockunlock.lu_is_arg };
 		    lval_root = &root;
-		    res = exec_command(iptr,
+		    int res = exec_command(iptr,
 					iptr->isn_arg.lockunlock.lu_string);
 		    clear_tv(root.lr_tv);
 		    lval_root = lval_root_save;