Implement Code actions with autofix

README.md

@@ -103,6 +103,7 @@ The following options are currently available.
 | --- | --- | --- | --- |
 | `enable_snippets` | `bool` | `false` | Enables snippet completions when the client also supports them. |
 | `enable_ast_check_diagnostics` | `bool` | `true`| Whether to enable ast-check diagnostics |
+| `enable_autofix` | `bool` | `false`| Whether to automatically fix errors on save. Currently supports adding and removing discards. |
 | `enable_import_embedfile_argument_completions` | `bool` | `false` | Whether to enable import/embedFile argument completions |
 | `zig_lib_path` | `?[]const u8` | `null` | zig library path, e.g. `/path/to/zig/lib/zig`, used to analyze std library imports. |
 | `zig_exe_path` | `?[]const u8` | `null` | zig executable path, e.g. `/path/to/zig/zig`, used to run the custom build runner. If `null`, zig is looked up in `PATH`. Will be used to infer the zig standard library path if none is provided. |

schema.json

@@ -14,6 +14,11 @@
             "type": "boolean",
             "default": "true"
         },
+        "enable_autofix": {
+            "description": "Whether to automatically fix errors on save. Currently supports adding and removing discards.",
+            "type": "boolean",
+            "default": "false"
+        },
         "enable_import_embedfile_argument_completions": {
             "description": "Whether to enable import/embedFile argument completions",
             "type": "boolean",

src/Config.zig

@@ -16,6 +16,10 @@ enable_snippets: bool = false,
 /// Whether to enable ast-check diagnostics
 enable_ast_check_diagnostics: bool = true,
 
+/// Whether to automatically fix errors on save.
+/// Currently supports adding and removing discards.
+enable_autofix: bool = false,
+
 /// Whether to enable import/embedFile argument completions (NOTE: these are triggered manually as updating the autotrigger characters may cause issues)
 enable_import_embedfile_argument_completions: bool = false,
 

src/analysis.zig

@@ -1844,7 +1844,10 @@ pub const Declaration = union(enum) {
     /// Index of the ast node
     ast_node: Ast.Node.Index,
     /// Function parameter
-    param_decl: Ast.full.FnProto.Param,
+    param_payload: struct {
+        param: Ast.full.FnProto.Param,
+        func: Ast.Node.Index,
+    },
     pointer_payload: struct {
         name: Ast.TokenIndex,
         condition: Ast.Node.Index,
@@ -1870,7 +1873,7 @@ pub const DeclWithHandle = struct {
         const tree = self.handle.tree;
         return switch (self.decl.*) {
             .ast_node => |n| getDeclNameToken(tree, n).?,
-            .param_decl => |p| p.name_token.?,
+            .param_payload => |pp| pp.param.name_token.?,
             .pointer_payload => |pp| pp.name,
             .array_payload => |ap| ap.identifier,
             .array_index => |ai| ai,
@@ -1897,7 +1900,8 @@ pub const DeclWithHandle = struct {
                 .{ .node = node, .handle = self.handle },
                 bound_type_params,
             ),
-            .param_decl => |param_decl| {
+            .param_payload => |pay| {
+                const param_decl = pay.param;
                 if (isMetaType(self.handle.tree, param_decl.type_expr)) {
                     var bound_param_it = bound_type_params.iterator();
                     while (bound_param_it.next()) |entry| {
@@ -2555,7 +2559,7 @@ fn makeScopeInternal(allocator: std.mem.Allocator, context: ScopeContext, node_i
                     if (try scopes.items[scope_idx].decls.fetchPut(
                         allocator,
                         tree.tokenSlice(name_token),
-                        .{ .param_decl = param },
+                        .{ .param_payload = .{ .param = param, .func = node_idx } },
                     )) |existing| {
                         _ = existing;
                         // TODO record a redefinition error

src/ast.zig

@@ -896,6 +896,17 @@ pub fn lastToken(tree: Ast, node: Ast.Node.Index) Ast.TokenIndex {
     };
 }
 
+pub fn paramFirstToken(tree: Ast, param: Ast.full.FnProto.Param) Ast.TokenIndex {
+    return param.first_doc_comment orelse
+        param.comptime_noalias orelse
+        param.name_token orelse
+        tree.firstToken(param.type_expr);
+}
+
+pub fn paramLastToken(tree: Ast, param: Ast.full.FnProto.Param) Ast.TokenIndex {
+    return param.anytype_ellipsis3 orelse tree.lastToken(param.type_expr);
+}
+
 pub fn containerField(tree: Ast, node: Ast.Node.Index) ?Ast.full.ContainerField {
     return switch (tree.nodes.items(.tag)[node]) {
         .container_field => tree.containerField(node),