diff --git a/src/regexp.c b/src/regexp.c
index fada9fe..733d564 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -2544,12 +2544,12 @@
 			    case CLASS_ALNUM:
 				for (cu = 1; cu <= 255; cu++)
 				    if (isalnum(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_ALPHA:
 				for (cu = 1; cu <= 255; cu++)
 				    if (isalpha(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_BLANK:
 				regc(' ');
@@ -2558,32 +2558,32 @@
 			    case CLASS_CNTRL:
 				for (cu = 1; cu <= 255; cu++)
 				    if (iscntrl(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_DIGIT:
 				for (cu = 1; cu <= 255; cu++)
 				    if (VIM_ISDIGIT(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_GRAPH:
 				for (cu = 1; cu <= 255; cu++)
 				    if (isgraph(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_LOWER:
 				for (cu = 1; cu <= 255; cu++)
 				    if (MB_ISLOWER(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_PRINT:
 				for (cu = 1; cu <= 255; cu++)
 				    if (vim_isprintc(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_PUNCT:
 				for (cu = 1; cu <= 255; cu++)
 				    if (ispunct(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_SPACE:
 				for (cu = 9; cu <= 13; cu++)
@@ -2593,12 +2593,12 @@
 			    case CLASS_UPPER:
 				for (cu = 1; cu <= 255; cu++)
 				    if (MB_ISUPPER(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_XDIGIT:
 				for (cu = 1; cu <= 255; cu++)
 				    if (vim_isxdigit(cu))
-					regc(cu);
+					regmbc(cu);
 				break;
 			    case CLASS_TAB:
 				regc('\t');
diff --git a/src/testdir/test_regexp_utf8.vim b/src/testdir/test_regexp_utf8.vim
index f5d7ec9..cef2436 100644
--- a/src/testdir/test_regexp_utf8.vim
+++ b/src/testdir/test_regexp_utf8.vim
@@ -33,3 +33,59 @@
   set re=2
   call s:equivalence_test()
 endfunc
+
+func s:classes_test()
+  call assert_equal('Motörhead', matchstr('Motörhead', '[[:print:]]\+'))
+
+  let alphachars = ''
+  let lowerchars = ''
+  let upperchars = ''
+  let alnumchars = ''
+  let printchars = ''
+  let punctchars = ''
+  let xdigitchars = ''
+  let i = 1
+  while i <= 255
+    let c = nr2char(i)
+    if c =~ '[[:alpha:]]'
+      let alphachars .= c
+    endif
+    if c =~ '[[:lower:]]'
+      let lowerchars .= c
+    endif
+    if c =~ '[[:upper:]]'
+      let upperchars .= c
+    endif
+    if c =~ '[[:alnum:]]'
+      let alnumchars .= c
+    endif
+    if c =~ '[[:print:]]'
+      let printchars .= c
+    endif
+    if c =~ '[[:punct:]]'
+      let punctchars .= c
+    endif
+    if c =~ '[[:xdigit:]]'
+      let xdigitchars .= c
+    endif
+    let i += 1
+  endwhile
+
+  call assert_equal('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz', alphachars)
+  call assert_equal('abcdefghijklmnopqrstuvwxyzµßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ', lowerchars)
+  call assert_equal('ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ', upperchars)
+  call assert_equal('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz', alnumchars)
+  call assert_equal(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ', printchars)
+  call assert_equal('!"#$%&''()*+,-./:;<=>?@[\]^_`{|}~', punctchars)
+  call assert_equal('0123456789ABCDEFabcdef', xdigitchars)
+endfunc
+
+func Test_classes_re1()
+  set re=1
+  call s:classes_test()
+endfunc
+
+func Test_classes_re2()
+  set re=2
+  call s:classes_test()
+endfunc
diff --git a/src/version.c b/src/version.c
index 09372ef..a4f3252 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1783,
+/**/
     1782,
 /**/
     1781,