lsp: Add support for call hierarchies (#12556)

* LSP: Add support for call hierarchies

* LSP: Add support for call hierarchies

* LSP: Add support for call hierarchies

* LSP: Jump to call location

Jump to the call site instead of jumping to the definition of the
caller/callee.

* LSP: add tests for the call hierarchy callbacks

* Fix linting error

Co-authored-by: Cédric Barreteau <>

6 files changed, 217 insertions, 0 deletions

diff --git a/runtime/doc/lsp.txt b/runtime/doc/lsp.txt
index 15587955de..9f878ad8c7 100644
--- a/runtime/doc/lsp.txt
+++ b/runtime/doc/lsp.txt
@@ -837,6 +837,16 @@ workspace_symbol({query})                     *vim.lsp.buf.workspace_symbol()*
                 enter a string on the command line. An empty string means no
                 filtering is done.
 
+incoming_calls()                               *vim.lsp.buf.incoming_calls()*
+                Lists all the call sites of the symbol under the cursor in the
+                |quickfix| window. If the symbol can resolve to multiple
+                items, the user can pick one in the |inputlist|.
+
+outgoing_calls()                               *vim.lsp.buf.outgoing_calls()*
+                Lists all the items that are called by the symbol under the
+                cursor in the |quickfix| window. If the symbol can resolve to
+                multiple items, the user can pick one in the |inputlist|.
+
 
 ==============================================================================
 Lua module: vim.lsp.callbacks                                  *lsp-callbacks*
diff --git a/runtime/lua/vim/lsp.lua b/runtime/lua/vim/lsp.lua
index 7442f0c0b5..6fe1d15b7e 100644
--- a/runtime/lua/vim/lsp.lua
+++ b/runtime/lua/vim/lsp.lua
@@ -511,6 +511,7 @@ function lsp.start_client(config)
       or (not client.resolved_capabilities.type_definition and method == 'textDocument/typeDefinition')
       or (not client.resolved_capabilities.document_symbol and method == 'textDocument/documentSymbol')
       or (not client.resolved_capabilities.workspace_symbol and method == 'textDocument/workspaceSymbol')
+      or (not client.resolved_capabilities.call_hierarchy and method == 'textDocument/prepareCallHierarchy')
     then
       callback(unsupported_method(method), method, nil, client_id, bufnr)
       return
diff --git a/runtime/lua/vim/lsp/buf.lua b/runtime/lua/vim/lsp/buf.lua
index 839e00c67d..476bb3ba6f 100644
--- a/runtime/lua/vim/lsp/buf.lua
+++ b/runtime/lua/vim/lsp/buf.lua
@@ -143,6 +143,38 @@ function M.document_symbol()
   request('textDocument/documentSymbol', params)
 end
 
+local function pick_call_hierarchy_item(call_hierarchy_items)
+  if not call_hierarchy_items then return end
+  if #call_hierarchy_items == 1 then
+    return call_hierarchy_items[1]
+  end
+  local items = {}
+  for i, item in ipairs(call_hierarchy_items) do
+    local entry = item.detail or item.name
+    table.insert(items, string.format("%d. %s", i, entry))
+  end
+  local choice = vim.fn.inputlist(items)
+  if choice < 1 or choice > #items then
+    return
+  end
+  return choice
+end
+
+function M.incoming_calls()
+  local params = util.make_position_params()
+  request('textDocument/prepareCallHierarchy', params, function(_, _, result)
+    local call_hierarchy_item = pick_call_hierarchy_item(result)
+    vim.lsp.buf_request(0, 'callHierarchy/incomingCalls', { item = call_hierarchy_item })
+  end)
+end
+
+function M.outgoing_calls()
+  local params = util.make_position_params()
+  request('textDocument/prepareCallHierarchy', params, function(_, _, result)
+    local call_hierarchy_item = pick_call_hierarchy_item(result)
+    vim.lsp.buf_request(0, 'callHierarchy/outgoingCalls', { item = call_hierarchy_item })
+  end)
+end
 
 --- Lists all symbols in the current workspace in the quickfix window.
 ---
diff --git a/runtime/lua/vim/lsp/callbacks.lua b/runtime/lua/vim/lsp/callbacks.lua
index 4b14f0132d..1ed58995d0 100644
--- a/runtime/lua/vim/lsp/callbacks.lua
+++ b/runtime/lua/vim/lsp/callbacks.lua
@@ -214,6 +214,33 @@ M['textDocument/documentHighlight'] = function(_, _, result, _)
   util.buf_highlight_references(bufnr, result)
 end
 
+-- direction is "from" for incoming calls and "to" for outgoing calls
+local make_call_hierarchy_callback = function(direction)
+  -- result is a CallHierarchy{Incoming,Outgoing}Call[]
+  return function(_, _, result)
+    if not result then return end
+    local items = {}
+    for _, call_hierarchy_call in pairs(result) do
+      local call_hierarchy_item = call_hierarchy_call[direction]
+      for _, range in pairs(call_hierarchy_call.fromRanges) do
+        table.insert(items, {
+          filename = assert(vim.uri_to_fname(call_hierarchy_item.uri)),
+          text = call_hierarchy_item.name,
+          lnum = range.start.line + 1,
+          col = range.start.character + 1,
+        })
+      end
+    end
+    util.set_qflist(items)
+    api.nvim_command("copen")
+    api.nvim_command("wincmd p")
+  end
+end
+
+M['callHierarchy/incomingCalls'] = make_call_hierarchy_callback('from')
+
+M['callHierarchy/outgoingCalls'] = make_call_hierarchy_callback('to')
+
 M['window/logMessage'] = function(_, _, result, client_id)
   local message_type = result.type
   local message = result.message
diff --git a/runtime/lua/vim/lsp/protocol.lua b/runtime/lua/vim/lsp/protocol.lua
index 4fded1961d..ef5e08680e 100644
--- a/runtime/lua/vim/lsp/protocol.lua
+++ b/runtime/lua/vim/lsp/protocol.lua
@@ -713,6 +713,9 @@ function protocol.make_client_capabilities()
       };
       applyEdit = true;
     };
+    callHierarchy = {
+      dynamicRegistration = false;
+    };
     experimental = nil;
   }
 end
@@ -912,6 +915,7 @@ function protocol.resolve_capabilities(server_capabilities)
   general_properties.workspace_symbol = server_capabilities.workspaceSymbolProvider or false
   general_properties.document_formatting = server_capabilities.documentFormattingProvider or false
   general_properties.document_range_formatting = server_capabilities.documentRangeFormattingProvider or false
+  general_properties.call_hierarchy = server_capabilities.callHierarchyProvider or false
 
   if server_capabilities.codeActionProvider == nil then
     general_properties.code_action = false
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 1b022f50df..aaa28390ea 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -1497,4 +1497,147 @@ describe('LSP', function()
     it('with softtabstop = 0', function() test_tabstop(2, 0) end)
     it('with softtabstop = -1', function() test_tabstop(3, -1) end)
   end)
+
+  describe('vim.lsp.buf.outgoing_calls', function()
+    it('does nothing for an empty response', function()
+      local qflist_count = exec_lua([=[
+        require'vim.lsp.callbacks'['callHierarchy/outgoingCalls']()
+        return #vim.fn.getqflist()
+      ]=])
+      eq(0, qflist_count)
+    end)
+
+    it('opens the quickfix list with the right caller', function()
+      local qflist = exec_lua([=[
+        local rust_analyzer_response = { {
+          fromRanges = { {
+            ['end'] = {
+              character = 7,
+              line = 3
+            },
+            start = {
+              character = 4,
+              line = 3
+            }
+          } },
+          to = {
+            detail = "fn foo()",
+            kind = 12,
+            name = "foo",
+            range = {
+              ['end'] = {
+                character = 11,
+                line = 0
+              },
+              start = {
+                character = 0,
+                line = 0
+              }
+            },
+            selectionRange = {
+              ['end'] = {
+                character = 6,
+                line = 0
+              },
+              start = {
+              character = 3,
+              line = 0
+              }
+            },
+            uri = "file:///src/main.rs"
+          }
+        } }
+        local callback = require'vim.lsp.callbacks'['callHierarchy/outgoingCalls']
+        callback(nil, nil, rust_analyzer_response)
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = { {
+        bufnr = 2,
+        col = 5,
+        lnum = 4,
+        module = "",
+        nr = 0,
+        pattern = "",
+        text = "foo",
+        type = "",
+        valid = 1,
+        vcol = 0
+      } }
+
+      eq(expected, qflist)
+    end)
+  end)
+
+  describe('vim.lsp.buf.incoming_calls', function()
+    it('does nothing for an empty response', function()
+      local qflist_count = exec_lua([=[
+        require'vim.lsp.callbacks'['callHierarchy/incomingCalls']()
+        return #vim.fn.getqflist()
+      ]=])
+      eq(0, qflist_count)
+    end)
+
+    it('opens the quickfix list with the right callee', function()
+      local qflist = exec_lua([=[
+        local rust_analyzer_response = { {
+          from = {
+            detail = "fn main()",
+            kind = 12,
+            name = "main",
+            range = {
+              ['end'] = {
+                character = 1,
+                line = 4
+              },
+              start = {
+                character = 0,
+                line = 2
+              }
+            },
+            selectionRange = {
+              ['end'] = {
+                character = 7,
+                line = 2
+              },
+              start = {
+                character = 3,
+                line = 2
+              }
+            },
+            uri = "file:///src/main.rs"
+          },
+          fromRanges = { {
+            ['end'] = {
+              character = 7,
+              line = 3
+            },
+            start = {
+              character = 4,
+              line = 3
+            }
+          } }
+        } }
+
+        local callback = require'vim.lsp.callbacks'['callHierarchy/incomingCalls']
+        callback(nil, nil, rust_analyzer_response)
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = { {
+        bufnr = 2,
+        col = 5,
+        lnum = 4,
+        module = "",
+        nr = 0,
+        pattern = "",
+        text = "main",
+        type = "",
+        valid = 1,
+        vcol = 0
+      } }
+
+      eq(expected, qflist)
+    end)
+  end)
 end)