parser: add notes to decl_between_fields error

3 files changed, 38 insertions, 0 deletions

diff --git a/lib/std/zig/Ast.zig b/lib/std/zig/Ast.zig
index 5501352084..a68959837a 100644
--- a/lib/std/zig/Ast.zig
+++ b/lib/std/zig/Ast.zig
@@ -329,6 +329,13 @@ pub fn renderError(tree: Ast, parse_error: Error, stream: anytype) !void {
             return stream.writeAll("expected field initializer");
         },
 
+        .previous_field => {
+            return stream.writeAll("field before declarations here");
+        },
+        .next_field => {
+            return stream.writeAll("field after declarations here");
+        },
+
         .expected_token => {
             const found_tag = token_tags[parse_error.token + @boolToInt(parse_error.token_is_prev)];
             const expected_symbol = parse_error.extra.expected_tag.symbol();
@@ -2470,6 +2477,7 @@ pub const full = struct {
 
 pub const Error = struct {
     tag: Tag,
+    is_note: bool = false,
     /// True if `token` points to the token before the token causing an issue.
     token_is_prev: bool = false,
     token: TokenIndex,
@@ -2527,6 +2535,9 @@ pub const Error = struct {
         expected_comma_after_switch_prong,
         expected_initializer,
 
+        previous_field,
+        next_field,
+
         /// `expected_tag` is populated.
         expected_token,
     };
diff --git a/lib/std/zig/parse.zig b/lib/std/zig/parse.zig
index 46d2b0f49e..2578629af5 100644
--- a/lib/std/zig/parse.zig
+++ b/lib/std/zig/parse.zig
@@ -91,6 +91,9 @@ const Parser = struct {
     extra_data: std.ArrayListUnmanaged(Node.Index),
     scratch: std.ArrayListUnmanaged(Node.Index),
 
+    /// Used for the error note of decl_between_fields error.
+    last_field: TokenIndex = undefined,
+
     const SmallSpan = union(enum) {
         zero_or_one: Node.Index,
         multi: Node.SubRange,
@@ -270,6 +273,8 @@ const Parser = struct {
                 .keyword_comptime => switch (p.token_tags[p.tok_i + 1]) {
                     .identifier => {
                         p.tok_i += 1;
+                        const identifier = p.tok_i;
+                        defer p.last_field = identifier;
                         const container_field = try p.expectContainerFieldRecoverable();
                         if (container_field != 0) {
                             switch (field_state) {
@@ -280,6 +285,16 @@ const Parser = struct {
                                         .tag = .decl_between_fields,
                                         .token = p.nodes.items(.main_token)[node],
                                     });
+                                    try p.warnMsg(.{
+                                        .tag = .previous_field,
+                                        .is_note = true,
+                                        .token = p.last_field,
+                                    });
+                                    try p.warnMsg(.{
+                                        .tag = .next_field,
+                                        .is_note = true,
+                                        .token = identifier,
+                                    });
                                     // Continue parsing; error will be reported later.
                                     field_state = .err;
                                 },
@@ -373,6 +388,8 @@ const Parser = struct {
                     trailing = p.token_tags[p.tok_i - 1] == .semicolon;
                 },
                 .identifier => {
+                    const identifier = p.tok_i;
+                    defer p.last_field = identifier;
                     const container_field = try p.expectContainerFieldRecoverable();
                     if (container_field != 0) {
                         switch (field_state) {
@@ -383,6 +400,14 @@ const Parser = struct {
                                     .tag = .decl_between_fields,
                                     .token = p.nodes.items(.main_token)[node],
                                 });
+                                try p.warnMsg(.{
+                                    .tag = .previous_field,
+                                    .token = p.last_field,
+                                });
+                                try p.warnMsg(.{
+                                    .tag = .next_field,
+                                    .token = identifier,
+                                });
                                 // Continue parsing; error will be reported later.
                                 field_state = .err;
                             },
diff --git a/lib/std/zig/parser_test.zig b/lib/std/zig/parser_test.zig
index 9bf7ae8da9..0c79b3b187 100644
--- a/lib/std/zig/parser_test.zig
+++ b/lib/std/zig/parser_test.zig
@@ -226,6 +226,8 @@ test "zig fmt: decl between fields" {
         \\};
     , &[_]Error{
         .decl_between_fields,
+        .previous_field,
+        .next_field,
     });
 }