overlays: remove 'nvim-treesitter-legacy-shim'

With the migration complete, I do not need it anymore.

This reverts commit bf260de243.

modules/home/vim/default.nix

@@ -60,8 +60,8 @@ in
       nvim-lspconfig # Easy LSP configuration
       lsp-format-nvim # Simplified formatting configuration
       none-ls-nvim # LSP integration for linters and formatters
-      nvim-treesitter-legacy.withAllGrammars # Better highlighting
-      nvim-treesitter-textobjects-legacy # More textobjects
+      nvim-treesitter.withAllGrammars # Better highlighting
+      nvim-treesitter-textobjects # More textobjects
       plenary-nvim # 'null-ls', 'telescope' dependency
 
       # Completion

modules/home/vim/plugin/settings/tree-sitter.lua

@@ -1,4 +1,4 @@
-local ts_config = require("nvim-treesitter.configs")
+local treesitter = require("nvim-treesitter")
 local ts_select = require("nvim-treesitter-textobjects.select")
 local ts_move = require("nvim-treesitter-textobjects.move")
 local utils = require("ambroisie.utils")
@@ -52,17 +52,6 @@ local moves = {
     { "[]", goto_previous_end("@class.outer"), desc = "Previous class end" },
 }
 
-ts_config.setup({
-    highlight = {
-        enable = true,
-        -- Avoid duplicate highlighting
-        additional_vim_regex_highlighting = false,
-    },
-    indent = {
-        enable = true,
-    },
-})
-
 require("nvim-treesitter-textobjects").setup({
     select = {
         -- Jump to matching text objects
@@ -73,3 +62,58 @@ require("nvim-treesitter-textobjects").setup({
         set_jumps = true,
     },
 })
+
+-- Automatically setup treesitter for supported filetypes
+local function treesitter_try_attach(buf, language)
+    -- Try to load language
+    -- NOTE: the best way I found to check if a filetype has a grammar
+    if not vim.treesitter.language.add(language) then
+        return false
+    end
+
+    -- Syntax highlighting
+    vim.treesitter.start(buf, language)
+    -- Indentation
+    vim.bo.indentexpr = "v:lua.require('nvim-treesitter').indentexpr()"
+
+    return true
+end
+
+vim.api.nvim_create_autocmd("FileType", {
+    pattern = "*",
+    group = vim.api.nvim_create_augroup("treesitter_attach", { clear = true }),
+    callback = function(args)
+        local buf, filetype = args.buf, args.match
+        local language = vim.treesitter.language.get_lang(filetype)
+        if not language then
+            return
+        end
+        treesitter_try_attach(buf, language)
+    end,
+})
+
+-- FIXME: is this more correct?
+--[[
+local installable_parsers = require("nvim-treesitter").get_available()
+
+vim.api.nvim_create_autocmd("FileType", {
+    pattern = "*",
+    group = vim.api.nvim_create_augroup("treesitter_attach", { clear = true }),
+    callback = function(args)
+        local buf, filetype = args.buf, args.match
+        local language = vim.treesitter.language.get_lang(filetype)
+        if not language then
+            return
+        end
+
+        if not treesitter_try_attach(buf, language) then
+            if vim.tbl_contains(installable_parsers, language) then
+                -- Not already installed, so try to install them via nvim-treesitter if possible
+                require("nvim-treesitter").install(language):await(function()
+                    treesitter_try_attach(buf, language)
+                end)
+            end
+        end
+    end,
+})
+--]]

overlays/nvim-treesitter-legacy-shim/default.nix

@@ -1,18 +0,0 @@
-final: prev:
-let
-  inherit (final) lib;
-  overrides = final: prev:
-    let
-      hasLegacyPackage = prev ? nvim-treesitter-legacy;
-    in
-    {
-      nvim-treesitter-textobjects-legacy = prev.nvim-treesitter-textobjects.overrideAttrs {
-        dependencies = [ final.nvim-treesitter-legacy ];
-      };
-    } // (lib.optionalAttrs (!hasLegacyPackage) {
-      nvim-treesitter-legacy = final.nvim-treesitter;
-    });
-in
-{
-  vimPlugins = prev.vimPlugins.extend (overrides);
-}