diff --git a/ale_linters/perl6/perl6.vim b/ale_linters/perl6/perl6.vim
index 326850a2..b33a0c51 100644
--- a/ale_linters/perl6/perl6.vim
+++ b/ale_linters/perl6/perl6.vim
@@ -21,9 +21,9 @@ function! ale_linters#perl6#perl6#GetCommand(buffer) abort
     \   . ' %t'
 endfunction
 
-function! ale_linters#perl6#perl6#ExtractError(dict, item, type) abort
+function! ale_linters#perl6#perl6#ExtractError(dict, item, type, buffer) abort
     let l:file = ''
-    let l:line = ''
+    let l:line = 1
     let l:column = ''
     let l:text = ''
     let l:pre = ''
@@ -32,26 +32,26 @@ function! ale_linters#perl6#perl6#ExtractError(dict, item, type) abort
     let l:linepatternmessage = 'at\s\+line\s\+\(\d\+\)'
 
     if has_key(a:dict[a:item], 'filename') && !empty(a:dict[a:item]['filename'])
-        let l:file .= a:dict[a:item]['filename']
+        let l:file = a:dict[a:item]['filename']
     endif
 
     if has_key(a:dict[a:item], 'line') && !empty(a:dict[a:item]['line'])
-      let l:line .= a:dict[a:item]['line']
+      let l:line = a:dict[a:item]['line']
       let l:counter -= 1
     endif
 
     if has_key(a:dict[a:item], 'column') && !empty(a:dict[a:item]['column'])
-        let l:column .= a:dict[a:item]['column']
+        let l:column = a:dict[a:item]['column']
     endif
 
     if has_key(a:dict[a:item], 'message') && !empty(a:dict[a:item]['message'])
-        let l:text .= substitute(a:dict[a:item]['message'], '\s*\n\s*', ' ', 'g')
+        let l:text = substitute(a:dict[a:item]['message'], '\s*\n\s*', ' ', 'g')
         let l:counter -= 1
     endif
 
     if has_key(a:dict[a:item], 'line-real') && !empty(a:dict[a:item]['line-real'])
         let l:end_line = l:line
-        let l:line .= a:dict[a:item]['line-real']
+        let l:line = a:dict[a:item]['line-real']
     endif
 
     for l:match in ale#util#GetMatches(l:text, l:linepatternmessage)
@@ -59,9 +59,11 @@ function! ale_linters#perl6#perl6#ExtractError(dict, item, type) abort
         let l:counter -= 1
     endfor
 
-    if l:counter < 1
+" Currently, filenames and line numbers are not always given in the error output
+    if l:counter < 2
+   \&& ( ale#path#IsBufferPath(a:buffer, l:file) || l:file is# '' )
         return {
-        \   'lnum': l:line,
+        \   'lnum': '' . l:line,
         \   'text': l:text,
         \   'type': a:type,
         \   'col': l:column,
@@ -69,6 +71,8 @@ function! ale_linters#perl6#perl6#ExtractError(dict, item, type) abort
         \   'code': a:item,
         \}
     endif
+
+    return ''
 endfunction
 
 function! ale_linters#perl6#perl6#Handle(buffer, lines) abort
@@ -102,13 +106,17 @@ function! ale_linters#perl6#perl6#Handle(buffer, lines) abort
                 if !empty(l:json[l:key]['sorrows'])
                     for l:dictionary in get(l:json[l:key], 'sorrows')
                         for l:item in keys(l:dictionary)
-                            call add(l:output,
+                            let l:result =
                             \   ale_linters#perl6#perl6#ExtractError(
                             \       l:dictionary,
                             \       l:item,
-                            \       'E'
+                            \       'E',
+                            \       a:buffer,
                             \   )
-                            \ )
+
+                            if l:result isnot# ''
+                              call add(l:output, l:result)
+                            endif
                         endfor
                     endfor
                 endif
@@ -116,20 +124,31 @@ function! ale_linters#perl6#perl6#Handle(buffer, lines) abort
                 if !empty(l:json[l:key]['worries'])
                     for l:dictionary in get(l:json[l:key], 'worries')
                         for l:item in keys(l:dictionary)
-                            call add(l:output,
+                            let l:result =
                             \   ale_linters#perl6#perl6#ExtractError(
                             \       l:dictionary,
                             \       l:item,
-                            \       'W'
+                            \       'W',
+                            \       a:buffer,
                             \   )
-                            \ )
+
+                            if l:result isnot# ''
+                              call add(l:output, l:result)
+                            endif
                         endfor
                     endfor
                 endif
             else
-                call add(l:output,
-                \   ale_linters#perl6#perl6#ExtractError(l:json, l:key, 'E')
-                \ )
+                let l:result = ale_linters#perl6#perl6#ExtractError(
+                \     l:json,
+                \     l:key,
+                \     'E',
+                \     a:buffer,
+                \   )
+
+                if l:result isnot# ''
+                  call add(l:output, l:result)
+                endif
             endif
         endfor
     endif
diff --git a/test/handler/test_perl6_handler.vader b/test/handler/test_perl6_handler.vader
index fbc5b12b..452a9174 100644
--- a/test/handler/test_perl6_handler.vader
+++ b/test/handler/test_perl6_handler.vader
@@ -200,3 +200,78 @@ Execute(The Perl6 linter should gracefully handle non-JSON messages):
   \   '    ------> /win<HERE> 3/',
   \   'Syntax OK'
   \ ])
+
+Execute(The Perl6 linter should gracefully handle messages without a line number):
+  call ale#test#SetFilename('bar.pl6')
+
+  AssertEqual
+  \ [
+  \    {
+  \     'lnum': '1',
+  \     'end_lnum': '',
+  \     'text': 'Cannot find method ''has_compile_time_value'' on object of type NQPMu',
+  \     'type': 'E',
+  \     'col' : '',
+  \     'code': 'X::AdHoc',
+  \    }
+  \ ],
+  \ ale_linters#perl6#perl6#Handle(bufnr(''), [
+  \   '{',
+  \     '"X::AdHoc" : {',
+  \       '"message" : "Cannot find method ''has_compile_time_value'' on object of type NQPMu",',
+  \       '"payload" : "Cannot find method ''has_compile_time_value'' on object of type NQPMu"',
+  \      '}',
+  \    '}',
+  \ ])
+
+Execute(The Perl6 linter should not include errors from a known separate file):
+  call ale#test#SetFilename('bar.pl6')
+
+  AssertEqual
+  \ [],
+  \ ale_linters#perl6#perl6#Handle(bufnr(''), [
+  \ '{
+  \   "X::Undeclared" : {
+  \     "highexpect" : [ ],
+  \     "is-compile-time" : 1,
+  \     "modules" : [ ],
+  \     "column" : null,
+  \     "pos" : 18,
+  \     "symbol" : "$tes",
+  \     "filename" : "foo.pl6",
+  \     "what" : "Variable",
+  \     "pre" : "my $test = 0; say ",
+  \     "post" : "$tes",
+  \     "suggestions" : [
+  \       "$res",
+  \       "$test"
+  \     ],
+  \     "line" : 6,
+  \     "message" : "Variable ''$tes'' is not declared. Did you mean any of these?\n    $res\n    $test\n"
+  \   }
+  \ }'
+  \ ])
+
+Execute(The Perl6 linter should not ignore errors without a filename):
+  call ale#test#SetFilename('bar.pl6')
+
+  AssertEqual
+  \ [
+  \    {
+  \     'lnum': '3',
+  \     'end_lnum': '',
+  \     'text': 'Cannot find method ''has_compile_time_value'' on object of type NQPMu',
+  \     'type': 'E',
+  \     'col' : '',
+  \     'code': 'X::AdHoc',
+  \    }
+  \ ],
+  \ ale_linters#perl6#perl6#Handle(bufnr(''), [
+  \   '{',
+  \     '"X::AdHoc" : {',
+  \       '"line" : 3,',
+  \       '"message" : "Cannot find method ''has_compile_time_value'' on object of type NQPMu",',
+  \       '"payload" : "Cannot find method ''has_compile_time_value'' on object of type NQPMu"',
+  \      '}',
+  \    '}',
+  \ ])