diff --git a/R/parser.R b/R/parser.R
index 3b66e011f3..217e287c01 100644
--- a/R/parser.R
+++ b/R/parser.R
@@ -400,38 +400,17 @@ parse_chunk = function(x, rc = knit_patterns$get('ref.chunk')) {
 
 # filter chunk.end lines that don't actually end a chunk
 filter_chunk_end = function(chunk.begin, chunk.end, lines = NULL, patterns = NULL) {
-  keys = c('chunk.begin', 'chunk.end')
-  if (identical(patterns[keys], all_patterns[['md']][keys])) {
-    filter_chunk_end_md(chunk.begin, chunk.end, lines)
-  } else {
-    filter_chunk_end_general(chunk.begin, chunk.end)
-  }
-}
-
-filter_chunk_end_general = function(chunk.begin, chunk.end) {
-  in.chunk = FALSE
-  fun = function(is.begin, is.end) {
-    if (in.chunk && is.end) {
-      in.chunk <<- FALSE
-      return(TRUE)
-    }
-    if (!in.chunk && is.begin) in.chunk <<- TRUE
-    FALSE
-  }
-  mapply(fun, chunk.begin, chunk.end)
-}
-
-filter_chunk_end_md = function(chunk.begin, chunk.end, lines) {
   in.chunk = FALSE
-  expected_end = NA_character_
+  is.md = identical(patterns, all_patterns[['md']])
+  pattern.end = NA_character_
   fun = function(is.begin, is.end, line) {
-    if (in.chunk && is.end && grepl(expected_end, line)) {
+    if (in.chunk && is.end && (is.na(pattern.end) || grepl(pattern.end, line))) {
       in.chunk <<- FALSE
       return(TRUE)
     }
     if (!in.chunk && is.begin) {
       in.chunk <<- TRUE
-      expected_end <<- paste0(sub('(^[\t >]*```+).*', '\\1', line), "\\s*$")
+      if (is.md) pattern.end <<- paste0(sub('(^[\t >]*```+).*', '\\1', line), "\\s*$")
     }
     FALSE
   }