E363.patch

diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 859fbe8f7..048bf0da2 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -5176,6 +5176,8 @@ A jump table for the options with a short description can be found at |Q_op|.
        Running into the limit often means that the pattern is very
        inefficient or too complex.  This may already happen with the pattern
        "\(.\)*" on a very long line.  ".*" works much better.
+        Might also happen, on redraw, when syntax rules try to match a complex
+        file structure.
        Vim may run out of memory before hitting the 'maxmempattern' limit.

                                                *'maxmemtot'* *'mmt'*
diff --git a/runtime/pack/dist/opt/matchit/plugin/matchit.vim b/runtime/pack/dist/opt/matchit/plugin/matchit.vim
index 4c9b84592..d9bc54ae1 100644
--- a/runtime/pack/dist/opt/matchit/plugin/matchit.vim
+++ b/runtime/pack/dist/opt/matchit/plugin/matchit.vim
@@ -720,10 +720,16 @@ fun! s:MultiMatch(spflag, mode)
   let openpat = substitute(openpat, ',', '\\|', 'g')
   let closepat = substitute(close, '\(\\\@<!\(\\\\\)*\)\@<=\\(', '\\%(', 'g')
   let closepat = substitute(closepat, ',', '\\|', 'g')
+
   if skip =~ 'synID' && !(has("syntax") && exists("g:syntax_on"))
     let skip = '0'
   else
-    execute "if " . skip . "| let skip = '0' | endif"
+    try
+      execute "if " . skip . "| let skip = '0' | endif"
+    catch /^Vim\%((\a\+)\)\=:E363/
+      " We won't find anything, so skip searching, should keep Vim responsive.
+      return
+    endtry
   endif
   mark '
   let level = v:count1
diff --git a/runtime/plugin/matchparen.vim b/runtime/plugin/matchparen.vim
index 5db1f64c7..29e33e996 100644
--- a/runtime/plugin/matchparen.vim
+++ b/runtime/plugin/matchparen.vim
@@ -107,6 +107,7 @@ function! s:Highlight_Matching_Pair()
   " certain syntax types (string, comment, etc.), for use as searchpairpos()'s
   " skip argument.
   " We match "escape" for special items, such as lispEscapeSpecial.
+  " Note: this may throw E363: pattern uses more memory than 'maxmempattern'
   let s_skip = '!empty(filter(map(synstack(line("."), col(".")), ''synIDattr(v:val, "name")''), ' .
        \ '''v:val =~? "string\\|character\\|singlequote\\|escape\\|comment"''))'
   " If executing the expression determines that the cursor is currently in
@@ -114,7 +115,16 @@ function! s:Highlight_Matching_Pair()
   " within those syntax types (i.e., not skip).  Otherwise, the cursor is
   " outside of the syntax types and s_skip should keep its value so we skip any
   " matching pair inside the syntax types.
-  execute 'if' s_skip '| let s_skip = 0 | endif'
+  if !has("syntax") || !exists("g:syntax_on")
+    let s:skip = 0
+  else
+    try
+      execute 'if' s_skip '| let s_skip = 0 | endif'
+    catch /^Vim\%((\a\+)\)\=:E363/
+      " We won't find anything, so skip searching, should keep Vim responsive.
+      return
+    endtry
+  endif

   " Limit the search to lines visible in the window.
   let stoplinebottom = line('w$')