diff --git a/src/blob.c b/src/blob.c
index fc1d3f6..c260a43 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -114,13 +114,16 @@
     blob_T	*b1,
     blob_T	*b2)
 {
-    int i;
+    int	    i;
+    int	    len1 = blob_len(b1);
+    int	    len2 = blob_len(b2);
 
-    if (b1 == NULL || b2 == NULL)
-	return FALSE;
+    // empty and NULL are considered the same
+    if (len1 == 0 && len2 == 0)
+	return TRUE;
     if (b1 == b2)
 	return TRUE;
-    if (blob_len(b1) != blob_len(b2))
+    if (len1 != len2)
 	return FALSE;
 
     for (i = 0; i < b1->bv_ga.ga_len; i++)
diff --git a/src/eval.c b/src/eval.c
index 59bddb8..78e4eae 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1983,9 +1983,9 @@
 		}
 		if (rettv != NULL
 			&& !(rettv->v_type == VAR_LIST
-			    || rettv->vval.v_list != NULL)
+						 && rettv->vval.v_list != NULL)
 			&& !(rettv->v_type == VAR_BLOB
-			    || rettv->vval.v_blob != NULL))
+						&& rettv->vval.v_blob != NULL))
 		{
 		    if (!quiet)
 			EMSG(_("E709: [:] requires a List or Blob value"));
@@ -2109,6 +2109,8 @@
 	}
 	else if (lp->ll_tv->v_type == VAR_BLOB)
 	{
+	    long bloblen = blob_len(lp->ll_tv->vval.v_blob);
+
 	    /*
 	     * Get the number and item for the only or first index of the List.
 	     */
@@ -2120,16 +2122,26 @@
 	    clear_tv(&var1);
 
 	    if (lp->ll_n1 < 0
-		    || lp->ll_n1 > blob_len(lp->ll_tv->vval.v_blob))
+		    || lp->ll_n1 > bloblen
+		    || (lp->ll_range && lp->ll_n1 == bloblen))
 	    {
 		if (!quiet)
-		    EMSGN(_(e_listidx), lp->ll_n1);
+		    EMSGN(_(e_blobidx), lp->ll_n1);
+		clear_tv(&var2);
 		return NULL;
 	    }
 	    if (lp->ll_range && !lp->ll_empty2)
 	    {
 		lp->ll_n2 = (long)tv_get_number(&var2);
 		clear_tv(&var2);
+		if (lp->ll_n2 < 0
+			|| lp->ll_n2 >= bloblen
+			|| lp->ll_n2 < lp->ll_n1)
+		{
+		    if (!quiet)
+			EMSGN(_(e_blobidx), lp->ll_n2);
+		    return NULL;
+		}
 	    }
 	    lp->ll_blob = lp->ll_tv->vval.v_blob;
 	    lp->ll_tv = NULL;
@@ -2241,6 +2253,7 @@
 	if (lp->ll_blob != NULL)
 	{
 	    int	    error = FALSE, val;
+
 	    if (op != NULL && *op != '=')
 	    {
 		EMSG2(_(e_letwrong), op);
@@ -2249,17 +2262,23 @@
 
 	    if (lp->ll_range && rettv->v_type == VAR_BLOB)
 	    {
-		int	i;
+		int	il, ir;
 
-		if (blob_len(rettv->vval.v_blob) != blob_len(lp->ll_blob))
+		if (lp->ll_empty2)
+		    lp->ll_n2 = blob_len(lp->ll_blob) - 1;
+
+		if (lp->ll_n2 - lp->ll_n1 + 1 != blob_len(rettv->vval.v_blob))
 		{
-		    EMSG(_("E972: Blob value has more items than target"));
+		    EMSG(_("E972: Blob value does not have the right number of bytes"));
 		    return;
 		}
+		if (lp->ll_empty2)
+		    lp->ll_n2 = blob_len(lp->ll_blob);
 
-		for (i = lp->ll_n1; i <= lp->ll_n2; i++)
-		    blob_set(lp->ll_blob, i,
-			    blob_get(rettv->vval.v_blob, i));
+		ir = 0;
+		for (il = lp->ll_n1; il <= lp->ll_n2; il++)
+		    blob_set(lp->ll_blob, il,
+			    blob_get(rettv->vval.v_blob, ir++));
 	    }
 	    else
 	    {
@@ -2278,8 +2297,7 @@
 			if (lp->ll_n1 == gap->ga_len)
 			    ++gap->ga_len;
 		    }
-		    else
-			EMSG(_(e_invrange));
+		    // error for invalid range was already given in get_lval()
 		}
 	    }
 	}
@@ -2312,7 +2330,7 @@
     else if (lp->ll_range)
     {
 	listitem_T *ll_li = lp->ll_li;
-	int ll_n1 = lp->ll_n1;
+	int	    ll_n1 = lp->ll_n1;
 
 	/*
 	 * Check whether any of the list items is locked
@@ -3354,6 +3372,8 @@
 {
     int		ret;
     char_u	*p;
+    int		did_emsg_before = did_emsg;
+    int		called_emsg_before = called_emsg;
 
     p = skipwhite(arg);
     ret = eval1(&p, rettv, evaluate);
@@ -3364,9 +3384,11 @@
 	/*
 	 * Report the invalid expression unless the expression evaluation has
 	 * been cancelled due to an aborting error, an interrupt, or an
-	 * exception.
+	 * exception, or we already gave a more specific error.
+	 * Also check called_emsg for when using assert_fails().
 	 */
-	if (!aborting())
+	if (!aborting() && did_emsg == did_emsg_before
+					  && called_emsg == called_emsg_before)
 	    EMSG2(_(e_invexpr2), arg);
 	ret = FAIL;
     }
@@ -4195,7 +4217,7 @@
 		    {
 			if (!vim_isxdigit(bp[1]))
 			{
-			    EMSG(_("E973: Blob literal should have an even number of hex characters'"));
+			    EMSG(_("E973: Blob literal should have an even number of hex characters"));
 			    vim_free(blob);
 			    ret = FAIL;
 			    break;
@@ -4632,7 +4654,7 @@
 		len = blob_len(rettv->vval.v_blob);
 		if (range)
 		{
-		    // The resulting variable is a substring.  If the indexes
+		    // The resulting variable is a sub-blob.  If the indexes
 		    // are out of range the result is empty.
 		    if (n1 < 0)
 		    {
@@ -8336,6 +8358,7 @@
     int		atstart = TRUE;
     char_u	numbuf[NUMBUFLEN];
     int		did_emsg_before = did_emsg;
+    int		called_emsg_before = called_emsg;
 
     if (eap->skip)
 	++emsg_skip;
@@ -8353,7 +8376,8 @@
 	     * has been cancelled due to an aborting error, an interrupt, or an
 	     * exception.
 	     */
-	    if (!aborting() && did_emsg == did_emsg_before)
+	    if (!aborting() && did_emsg == did_emsg_before
+					  && called_emsg == called_emsg_before)
 		EMSG2(_(e_invexpr2), p);
 	    need_clr_eos = FALSE;
 	    break;
diff --git a/src/evalfunc.c b/src/evalfunc.c
index a5bae56..c1c8c23 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -429,6 +429,7 @@
 static void f_test_override(typval_T *argvars, typval_T *rettv);
 static void f_test_garbagecollect_now(typval_T *argvars, typval_T *rettv);
 static void f_test_ignore_error(typval_T *argvars, typval_T *rettv);
+static void f_test_null_blob(typval_T *argvars, typval_T *rettv);
 #ifdef FEAT_JOB_CHANNEL
 static void f_test_null_channel(typval_T *argvars, typval_T *rettv);
 #endif
@@ -950,6 +951,7 @@
     {"test_feedinput",	1, 1, f_test_feedinput},
     {"test_garbagecollect_now",	0, 0, f_test_garbagecollect_now},
     {"test_ignore_error",	1, 1, f_test_ignore_error},
+    {"test_null_blob", 0, 0, f_test_null_blob},
 #ifdef FEAT_JOB_CHANNEL
     {"test_null_channel", 0, 0, f_test_null_channel},
 #endif
@@ -13902,6 +13904,13 @@
      ignore_error_for_testing(tv_get_string(&argvars[0]));
 }
 
+    static void
+f_test_null_blob(typval_T *argvars UNUSED, typval_T *rettv)
+{
+    rettv->v_type = VAR_BLOB;
+    rettv->vval.v_blob = NULL;
+}
+
 #ifdef FEAT_JOB_CHANNEL
     static void
 f_test_null_channel(typval_T *argvars UNUSED, typval_T *rettv)
diff --git a/src/testdir/test49.vim b/src/testdir/test49.vim
index 0f825a2..97088f0 100644
--- a/src/testdir/test49.vim
+++ b/src/testdir/test49.vim
@@ -1,6 +1,6 @@
 " Vim script language tests
 " Author:	Servatius Brandt <Servatius.Brandt@fujitsu-siemens.com>
-" Last Change:	2019 Jan 09
+" Last Change:	2019 Jan 13
 
 "-------------------------------------------------------------------------------
 " Test environment							    {{{1
@@ -3694,7 +3694,7 @@
 if ExtraVim(msgfile)
     try
 	Xpath 4194304				" X: 4194304
-	let x = novar	" error E121/E15; exception: E121
+	let x = novar	" error E121; exception: E121
     catch /E15:/	" should not catch
 	Xpath 8388608				" X: 0
     endtry
@@ -3702,7 +3702,7 @@
 endif
 
 Xpath 33554432					" X: 33554432
-if !MESSAGES('E121', "Undefined variable", 'E15', "Invalid expression")
+if !MESSAGES('E121', "Undefined variable")
     Xpath 67108864				" X: 0
 endif
 
diff --git a/src/testdir/test_assign.vim b/src/testdir/test_assign.vim
index 317d458..1715a3f 100644
--- a/src/testdir/test_assign.vim
+++ b/src/testdir/test_assign.vim
@@ -23,11 +23,11 @@
     let &t_k1 = old_t_k1
   endif
 
-  call assert_fails('let x = &t_xx', 'E15')
+  call assert_fails('let x = &t_xx', 'E113')
   let &t_xx = "yes"
   call assert_equal("yes", &t_xx)
   let &t_xx = ""
-  call assert_fails('let x = &t_xx', 'E15')
+  call assert_fails('let x = &t_xx', 'E113')
 endfunc
 
 func Test_let_option_error()
@@ -43,3 +43,11 @@
   call assert_equal("vert:|", &fillchars)
   let &fillchars = _w
 endfunc
+
+func Test_let_errors()
+  let s = 'abcd'
+  call assert_fails('let s[1] = 5', 'E689:')
+
+  let l = [1, 2, 3]
+  call assert_fails('let l[:] = 5', 'E709:')
+endfunc
diff --git a/src/testdir/test_blob.vim b/src/testdir/test_blob.vim
index 4ab28eb4..550b8f1 100644
--- a/src/testdir/test_blob.vim
+++ b/src/testdir/test_blob.vim
@@ -21,6 +21,12 @@
   call assert_equal(0xDE, get(b, 0))
   call assert_equal(0xEF, get(b, 3))
   call assert_fails('let x = get(b, 4)')
+
+  call assert_fails('let b = 0z1', 'E973:')
+  call assert_fails('let b = 0z1x', 'E973:')
+  call assert_fails('let b = 0z12345', 'E973:')
+
+  call assert_equal(0z, test_null_blob())
 endfunc
 
 " assignment to a blob
@@ -32,6 +38,45 @@
   let bcopy = b[:]
   call assert_equal(b, bcopy)
   call assert_false(b is bcopy)
+
+  let b = 0zDEADBEEF
+  let b2 = b
+  call assert_true(b is b2)
+  let b[:] = 0z11223344
+  call assert_equal(0z11223344, b)
+  call assert_equal(0z11223344, b2)
+  call assert_true(b is b2)
+
+  let b = 0zDEADBEEF
+  let b[3:] = 0z66
+  call assert_equal(0zDEADBE66, b)
+  let b[:1] = 0z8899
+  call assert_equal(0z8899BE66, b)
+
+  call assert_fails('let b[2:3] = 0z112233', 'E972:')
+  call assert_fails('let b[2:3] = 0z11', 'E972:')
+  call assert_fails('let b[3:2] = 0z', 'E979:')
+
+  let b = 0zDEADBEEF
+  let b += 0z99
+  call assert_equal(0zDEADBEEF99, b)
+
+  call assert_fails('let b .= 0z33', 'E734:')
+  call assert_fails('let b .= "xx"', 'E734:')
+  call assert_fails('let b += "xx"', 'E734:')
+  call assert_fails('let b[1:1] .= 0z55', 'E734:')
+endfunc
+
+func Test_blob_get_range()
+  let b = 0z0011223344
+  call assert_equal(0z2233, b[2:3])
+  call assert_equal(0z223344, b[2:-1])
+  call assert_equal(0z00, b[0:-5])
+  call assert_equal(0z, b[0:-11])
+  call assert_equal(0z44, b[-1:])
+  call assert_equal(0z0011223344, b[:])
+  call assert_equal(0z0011223344, b[:-1])
+  call assert_equal(0z, b[5:6])
 endfunc
 
 func Test_blob_to_string()
@@ -44,8 +89,12 @@
 func Test_blob_compare()
   let b1 = 0z0011
   let b2 = 0z1100
+  let b3 = 0z001122
+  call assert_true(b1 == b1)
   call assert_false(b1 == b2)
+  call assert_false(b1 == b3)
   call assert_true(b1 != b2)
+  call assert_true(b1 != b3)
   call assert_true(b1 == 0z0011)
 
   call assert_false(b1 is b2)
@@ -65,7 +114,7 @@
   let b[1] = 0x11
   let b[2] = 0x22
   call assert_equal(0z001122, b)
-  call assert_fails('let b[4] = 0x33')
+  call assert_fails('let b[4] = 0x33', 'E979:')
 endfunc
 
 func Test_blob_for_loop()
@@ -177,3 +226,15 @@
   call assert_equal('[222,173,190,239]', json_encode(0zDEADBEEF))
   call assert_equal('[]', json_encode(0z))
 endfunc
+
+func Test_blob_lock()
+  let b = 0z112233
+  lockvar b
+  call assert_fails('let b = 0z44', 'E741:')
+  unlockvar b
+  let b = 0z44
+endfunc
+
+func Test_blob_sort()
+  call assert_fails('call sort([1.0, 0z11], "f")', 'E975:')
+endfunc
diff --git a/src/testdir/test_eval_stuff.vim b/src/testdir/test_eval_stuff.vim
index a1aa788..dc3cb89 100644
--- a/src/testdir/test_eval_stuff.vim
+++ b/src/testdir/test_eval_stuff.vim
@@ -63,3 +63,9 @@
   call assert_fails("let v:oldfiles=''", 'E963:')
   call assert_equal(v_o, v:oldfiles)
 endfunc
+
+func Test_for_invalid()
+  call assert_fails("for x in 99", 'E714:')
+  call assert_fails("for x in 'asdf'", 'E714:')
+  call assert_fails("for x in {'a': 9}", 'E714:')
+endfunc
diff --git a/src/testdir/test_lambda.vim b/src/testdir/test_lambda.vim
index 7a31dcc..4ff3e20 100644
--- a/src/testdir/test_lambda.vim
+++ b/src/testdir/test_lambda.vim
@@ -49,7 +49,7 @@
 
 function Test_lambda_fails()
   call assert_equal(3, {a, b -> a + b}(1, 2))
-  call assert_fails('echo {a, a -> a + a}(1, 2)', 'E15:')
+  call assert_fails('echo {a, a -> a + a}(1, 2)', 'E853:')
   call assert_fails('echo {a, b -> a + b)}(1, 2)', 'E15:')
 endfunc
 
@@ -169,7 +169,7 @@
   let l:D = s:NewCounter2()
 
   call assert_equal(1, l:C())
-  call assert_fails(':call l:D()', 'E15:') " E121: then E15:
+  call assert_fails(':call l:D()', 'E121:')
   call assert_equal(2, l:C())
 endfunc
 
diff --git a/src/version.c b/src/version.c
index 448e27d..643830a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -796,6 +796,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    736,
+/**/
     735,
 /**/
     734,