Add textDocument/typeDefinition for LSP (#2226)

* Add textDocument/typeDefinition for LSP

Doc to spec https://microsoft.github.io/language-server-protocol/specification#textDocument_typeDefinition

This works like textDocument/definition but resolves a location of a
type of an expression under the cursor.

I'm not sure what to do with tsserver though.

* Fix passing column to LSP
* test_go_to_definition: wording
* Add tests for textDocument/typeDefinition
* Add docs for textDocument/typeDefinition

3 files changed, 41 insertions, 6 deletions

diff --git a/autoload/ale/definition.vim b/autoload/ale/definition.vim
index 79d12596..a732e501 100644
--- a/autoload/ale/definition.vim
+++ b/autoload/ale/definition.vim
@@ -57,7 +57,7 @@ function! ale#definition#HandleLSPResponse(conn_id, response) abort
     endif
 endfunction
 
-function! s:OnReady(linter, lsp_details, line, column, options, ...) abort
+function! s:OnReady(linter, lsp_details, line, column, options, capability, ...) abort
     let l:buffer = a:lsp_details.buffer
     let l:id = a:lsp_details.connection_id
 
@@ -80,7 +80,14 @@ function! s:OnReady(linter, lsp_details, line, column, options, ...) abort
         " 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.
-        let l:message = ale#lsp#message#Definition(l:buffer, a:line, a:column)
+        if a:capability is# 'definition'
+            let l:message = ale#lsp#message#Definition(l:buffer, a:line, a:column)
+        elseif a:capability is# 'typeDefinition'
+            let l:message = ale#lsp#message#TypeDefinition(l:buffer, a:line, a:column)
+        else
+            " XXX: log here?
+            return
+        endif
     endif
 
     let l:request_id = ale#lsp#Send(l:id, l:message)
@@ -90,7 +97,7 @@ function! s:OnReady(linter, lsp_details, line, column, options, ...) abort
     \}
 endfunction
 
-function! s:GoToLSPDefinition(linter, options) abort
+function! s:GoToLSPDefinition(linter, options, capability) abort
     let l:buffer = bufnr('')
     let [l:line, l:column] = getcurpos()[1:2]
     let l:lsp_details = ale#lsp_linter#StartLSP(l:buffer, a:linter)
@@ -105,15 +112,29 @@ function! s:GoToLSPDefinition(linter, options) abort
 
     let l:id = l:lsp_details.connection_id
 
-    call ale#lsp#WaitForCapability(l:id, 'definition', function('s:OnReady', [
-    \   a:linter, l:lsp_details, l:line, l:column, a:options
+    call ale#lsp#WaitForCapability(l:id, a:capability, function('s:OnReady', [
+    \   a:linter, l:lsp_details, l:line, l:column, a:options, a:capability
     \]))
 endfunction
 
 function! ale#definition#GoTo(options) abort
     for l:linter in ale#linter#Get(&filetype)
         if !empty(l:linter.lsp)
-            call s:GoToLSPDefinition(l:linter, a:options)
+            call s:GoToLSPDefinition(l:linter, a:options, 'definition')
+        endif
+    endfor
+endfunction
+
+function! ale#definition#GoToType(options) abort
+    for l:linter in ale#linter#Get(&filetype)
+        if !empty(l:linter.lsp)
+            " TODO: handle typeDefinition for tsserver if supported by the
+            " protocol
+            if l:linter.lsp is# 'tsserver'
+                continue
+            endif
+
+            call s:GoToLSPDefinition(l:linter, a:options, 'typeDefinition')
         endif
     endfor
 endfunction
diff --git a/autoload/ale/lsp.vim b/autoload/ale/lsp.vim
index f55096c2..95ab83cf 100644
--- a/autoload/ale/lsp.vim
+++ b/autoload/ale/lsp.vim
@@ -43,6 +43,7 @@ function! ale#lsp#Register(executable_or_address, project, init_options) abort
         \       'completion': 0,
         \       'completion_trigger_characters': [],
         \       'definition': 0,
+        \       'typeDefinition': 0,
         \       'symbol_search': 0,
         \   },
         \}
@@ -207,6 +208,10 @@ function! s:UpdateCapabilities(conn, capabilities) abort
         let a:conn.capabilities.definition = 1
     endif
 
+    if get(a:capabilities, 'typeDefinitionProvider') is v:true
+        let a:conn.capabilities.typeDefinition = 1
+    endif
+
     if get(a:capabilities, 'workspaceSymbolProvider') is v:true
         let a:conn.capabilities.symbol_search = 1
     endif
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
index a9921478..cc0b2227 100644
--- a/autoload/ale/lsp/message.vim
+++ b/autoload/ale/lsp/message.vim
@@ -124,6 +124,15 @@ function! ale#lsp#message#Definition(buffer, line, column) abort
     \}]
 endfunction
 
+function! ale#lsp#message#TypeDefinition(buffer, line, column) abort
+    return [0, 'textDocument/typeDefinition', {
+    \   'textDocument': {
+    \       'uri': ale#path#ToURI(expand('#' . a:buffer . ':p')),
+    \   },
+    \   'position': {'line': a:line - 1, 'character': a:column - 1},
+    \}]
+endfunction
+
 function! ale#lsp#message#References(buffer, line, column) abort
     return [0, 'textDocument/references', {
     \   'textDocument': {