patch 8.2.3263: Vim9: "..=" does not accept same types as the ".." operator

Problem:    Vim9: "..=" does not accept same types as the ".." operator.
Solution:   Convert value to string like ".." does. (issue #8664)

src/evalfunc.c

@@ -930,6 +930,13 @@ ret_first_arg(int argcount, type_T **argtypes)
     if (argcount > 0)
 	return argtypes[0];
     return &t_void;
+}
+    static type_T *
+ret_repeat(int argcount UNUSED, type_T **argtypes)
+{
+    if (argtypes[0] == &t_number)
+	return &t_string;
+    return argtypes[0];
 }
 // for map(): returns first argument but item type may differ
     static type_T *
@@ -1813,7 +1820,7 @@ static funcentry_T global_functions[] =
     {"rename",		2, 2, FEARG_1,	    arg2_string,
 			ret_number_bool,    f_rename},
     {"repeat",		2, 2, FEARG_1,	    arg2_repeat,
-			ret_first_arg,	    f_repeat},
+			ret_repeat,	    f_repeat},
     {"resolve",		1, 1, FEARG_1,	    arg1_string,
 			ret_string,	    f_resolve},
     {"reverse",		1, 1, FEARG_1,	    arg1_list_or_blob,

src/ex_docmd.c

@@ -664,8 +664,6 @@ do_cmdline(
 #endif
     static int	call_depth = 0;		// recursiveness
 #ifdef FEAT_EVAL
-    ESTACK_CHECK_DECLARATION
-
     // For every pair of do_cmdline()/do_one_cmd() calls, use an extra memory
     // location for storing error messages to be converted to an exception.
     // This ensures that the do_errthrow() call in do_one_cmd() does not
@@ -1397,6 +1395,7 @@ handle_did_throw()
 {
     char	*p = NULL;
     msglist_T	*messages = NULL;
+    ESTACK_CHECK_DECLARATION
 
     /*
      * If the uncaught exception is a user exception, report it as an

src/testdir/test_vim9_assign.vim

@@ -239,6 +239,32 @@ def Test_assignment()
   END
 enddef
 
+let g:someNumber = 43
+
+def Test_assign_concat()
+  var lines =<< trim END
+    var s = '-'
+    s ..= 99
+    s ..= true
+    s ..= '-'
+    s ..= v:null
+    s ..= g:someNumber
+    assert_equal('-99true-null43', s)
+  END
+  CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    var s = '-'
+    s ..= [1, 2]
+  END
+  CheckDefAndScriptFailure2(lines, 'E1105: Cannot convert list to string', 'E734: Wrong variable type for .=', 2)
+  lines =<< trim END
+    var s = '-'
+    s ..= {a: 2}
+  END
+  CheckDefAndScriptFailure2(lines, 'E1105: Cannot convert dict to string', 'E734: Wrong variable type for .=', 2)
+enddef
+
 def Test_assign_register()
   var lines =<< trim END
     @c = 'areg'

src/testdir/test_vim9_builtin.vim

@@ -2558,9 +2558,15 @@ enddef
 def Test_repeat()
   CheckDefAndScriptFailure2(['repeat(1.1, 2)'], 'E1013: Argument 1: type mismatch, expected string but got float', 'E1224: String, Number or List required for argument 1')
   CheckDefAndScriptFailure2(['repeat({a: 10}, 2)'], 'E1013: Argument 1: type mismatch, expected string but got dict<', 'E1224: String, Number or List required for argument 1')
-  assert_equal('aaa', repeat('a', 3))
-  assert_equal('111', repeat(1, 3))
-  assert_equal([1, 1, 1], repeat([1], 3))
+  var lines =<< trim END
+      assert_equal('aaa', repeat('a', 3))
+      assert_equal('111', repeat(1, 3))
+      assert_equal([1, 1, 1], repeat([1], 3))
+      var s = '-'
+      s ..= repeat(5, 3)
+      assert_equal('-555', s)
+  END
+  CheckDefAndScriptSuccess(lines)
 enddef
 
 def Test_resolve()

src/testdir/test_vim9_disassemble.vim

@@ -1254,7 +1254,7 @@ def Test_disassemble_for_loop_eval()
         'res ..= str\_s*' ..
         '\d\+ LOAD $0\_s*' ..
         '\d\+ LOAD $2\_s*' ..
-        '\d\+ CHECKTYPE string stack\[-1\]\_s*' ..
+        '\d 2STRING_ANY stack\[-1\]\_s*' ..
         '\d\+ CONCAT\_s*' ..
         '\d\+ STORE $0\_s*' ..
         'endfor\_s*' ..

src/version.c

@@ -755,6 +755,12 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3263,
+/**/
+    3262,
+/**/
+    3261,
 /**/
     3260,
 /**/

src/vim9compile.c

@@ -7086,18 +7086,23 @@ compile_assignment(char_u *arg, exarg_T *eap, cmdidx_T cmdidx, cctx_T *cctx)
 	    type_T	    *stacktype;
 
 	    if (*op == '.')
-		expected = &t_string;
+	    {
+		if (may_generate_2STRING(-1, FALSE, cctx) == FAIL)
+		    goto theend;
+	    }
 	    else
+	    {
 		expected = lhs.lhs_member_type;
-	    stacktype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-	    if (
+		stacktype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
+		if (
 #ifdef FEAT_FLOAT
-		// If variable is float operation with number is OK.
-		!(expected == &t_float && stacktype == &t_number) &&
+		    // If variable is float operation with number is OK.
+		    !(expected == &t_float && stacktype == &t_number) &&
 #endif
 		    need_type(stacktype, expected, -1, 0, cctx,
 							 FALSE, FALSE) == FAIL)
-		goto theend;
+		    goto theend;
+	    }
 
 	    if (*op == '.')
 	    {