diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index f814390..6a723a6 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -326,6 +326,14 @@ function! s:GetLSPCompletions(linter) abort
         \   b:ale_completion_info.prefix,
         \)
     else
+        " Send a message saying the buffer has changed first, otherwise
+        " completions won't know what text is nearby.
+        call ale#lsp#Send(
+        \   l:id,
+        \   ale#lsp#message#DidChange(l:buffer),
+        \   l:root
+        \)
+
         " For LSP completions, we need to clamp the column to the length of
         " the line. python-language-server and perhaps others do not implement
         " this correctly.
@@ -334,9 +342,9 @@ function! s:GetLSPCompletions(linter) abort
         \   b:ale_completion_info.line,
         \   min([
         \       b:ale_completion_info.line_length,
-        \       b:ale_completion_info.column
+        \       b:ale_completion_info.column,
         \   ]),
-        \   '',
+        \   ale#completion#GetTriggerCharacter(&filetype, b:ale_completion_info.prefix),
         \)
     endif
 
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
index a90d4e7..b3a039c 100644
--- a/autoload/ale/lsp/message.vim
+++ b/autoload/ale/lsp/message.vim
@@ -95,7 +95,7 @@ function! ale#lsp#message#Completion(buffer, line, column, trigger_character) ab
     \   'textDocument': {
     \       'uri': ale#path#ToURI(expand('#' . a:buffer . ':p')),
     \   },
-    \   'position': {'line': a:line - 1, 'character': a:column - 1},
+    \   'position': {'line': a:line - 1, 'character': a:column},
     \}]
 
     if !empty(a:trigger_character)
diff --git a/test/completion/test_lsp_completion_messages.vader b/test/completion/test_lsp_completion_messages.vader
index df340fb..f21acfb 100644
--- a/test/completion/test_lsp_completion_messages.vader
+++ b/test/completion/test_lsp_completion_messages.vader
@@ -15,7 +15,7 @@ Before:
 
   runtime autoload/ale/lsp.vim
 
-  let g:message = []
+  let g:message_list = []
   let g:Callback = ''
 
   function! ale#linter#StartLSP(buffer, linter, callback) abort
@@ -29,13 +29,13 @@ Before:
 
   " Replace the Send function for LSP, so we can monitor calls to it.
   function! ale#lsp#Send(conn_id, message, ...) abort
-    let g:message = a:message
+    call add(g:message_list, a:message)
   endfunction
 
 After:
   Restore
 
-  unlet! g:message
+  unlet! g:message_list
   unlet! g:Callback
   unlet! b:ale_old_omnifunc
   unlet! b:ale_old_completopt
@@ -75,8 +75,8 @@ Execute(The right message should be sent for the initial tsserver request):
   \ string(g:Callback)
   " We should send the right message.
   AssertEqual
-  \ [0, 'ts@completions', {'file': expand('%:p'), 'line': 1, 'offset': 3, 'prefix': 'fo'}],
-  \ g:message
+  \ [[0, 'ts@completions', {'file': expand('%:p'), 'line': 1, 'offset': 3, 'prefix': 'fo'}]],
+  \ g:message_list
   " We should set up the completion info correctly.
   AssertEqual
   \ {
@@ -118,7 +118,7 @@ Execute(The right message sent to the tsserver LSP when the first completion mes
 
   " The entry details messages should have been sent.
   AssertEqual
-  \ [
+  \ [[
   \   0,
   \   'ts@completionEntryDetails',
   \   {
@@ -127,8 +127,8 @@ Execute(The right message sent to the tsserver LSP when the first completion mes
   \     'offset': 1,
   \     'line': 1,
   \   },
-  \ ],
-  \ g:message
+  \ ]],
+  \ g:message_list
 
 Given python(Some Python file):
   foo
@@ -152,12 +152,23 @@ Execute(The right message should be sent for the initial LSP request):
   " We should send the right message.
   " The character index needs to be at most the index of the last character on
   " the line, or integration with pyls will be broken.
+  "
+  " We need to send the message for changing the document first.
   AssertEqual
-  \ [0, 'textDocument/completion', {
+  \ [
+  \   [1, 'textDocument/didChange', {
+  \     'textDocument': {
+  \         'uri': ale#path#ToURI(expand('%:p')),
+  \         'version': g:ale_lsp_next_version_id - 1,
+  \     },
+  \     'contentChanges': [{'text': join(getline(1, '$'), "\n") . "\n"}]
+  \   }],
+  \   [0, 'textDocument/completion', {
   \   'textDocument': {'uri': ale#path#ToURI(expand('%:p'))},
-  \   'position': {'line': 0, 'character': 2},
-  \ }],
-  \ g:message
+  \   'position': {'line': 0, 'character': 3},
+  \   }],
+  \ ],
+  \ g:message_list
   " We should set up the completion info correctly.
   AssertEqual
   \ {
diff --git a/test/lsp/test_lsp_client_messages.vader b/test/lsp/test_lsp_client_messages.vader
index bd0cd10..346f79c 100644
--- a/test/lsp/test_lsp_client_messages.vader
+++ b/test/lsp/test_lsp_client_messages.vader
@@ -110,7 +110,7 @@ Execute(ale#lsp#message#Completion() should return correct messages):
   \     'textDocument': {
   \         'uri': ale#path#ToURI(g:dir . '/foo/bar.ts'),
   \     },
-  \     'position': {'line': 11, 'character': 33},
+  \     'position': {'line': 11, 'character': 34},
   \   }
   \ ],
   \ ale#lsp#message#Completion(bufnr(''), 12, 34, '')
@@ -124,7 +124,7 @@ Execute(ale#lsp#message#Completion() should return correct messages with a trigg
   \     'textDocument': {
   \         'uri': ale#path#ToURI(g:dir . '/foo/bar.ts'),
   \     },
-  \     'position': {'line': 11, 'character': 33},
+  \     'position': {'line': 11, 'character': 34},
   \     'context': {'triggerKind': 2, 'triggerCharacter': '.'},
   \   }
   \ ],