From b3b6ce5b97c74cd174040ec635fb2d3f9a2a77b6 Mon Sep 17 00:00:00 2001
From: Swastik Baranwal <swstkbaranwal@gmail.com>
Date: Sun, 21 Jul 2024 16:11:01 +0530
Subject: [PATCH] checker: improve checks for embed in anon struct  (#21877)

---
 vlib/v/checker/checker.v                         | 16 ++++++++++++++++
 ...type_alias_decl_anon_struct_invalid_embed.out | 12 ++++++++++++
 .../type_alias_decl_anon_struct_invalid_embed.vv |  4 ++++
 .../tests/struct_anon_invalid_embed_err.out      |  6 ++++++
 .../tests/struct_anon_invalid_embed_err.vv       |  4 ++++
 5 files changed, 42 insertions(+)
 create mode 100644 vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.out
 create mode 100644 vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv
 create mode 100644 vlib/v/parser/tests/struct_anon_invalid_embed_err.out
 create mode 100644 vlib/v/parser/tests/struct_anon_invalid_embed_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index a2cb58297..a011bac38 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -561,6 +561,22 @@ fn (mut c Checker) alias_type_decl(node ast.AliasTypeDecl) {
 						c.error('unknown type `${ct_sym.name}`', node.type_pos)
 					}
 				}
+				// check if embed types are struct
+				for embed_type in parent_typ_sym.info.embeds {
+					final_embed_sym := c.table.final_sym(embed_type)
+					if final_embed_sym.kind != .struct_ {
+						c.error('cannot embed non-struct `${c.table.sym(embed_type).name}`',
+							node.type_pos)
+					}
+				}
+				if parent_typ_sym.info.is_anon {
+					for field in parent_typ_sym.info.fields {
+						if c.table.final_sym(field.typ).kind != .struct_ {
+							c.error('cannot embed non-struct `${c.table.sym(field.typ).name}`',
+								field.type_pos)
+						}
+					}
+				}
 			}
 		}
 		.array {
diff --git a/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.out b/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.out
new file mode 100644
index 000000000..663c448f3
--- /dev/null
+++ b/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.out
@@ -0,0 +1,12 @@
+vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv:2:16: error: cannot embed non-struct `Int`
+    1 | type Int = int
+    2 | type MyIndex = struct {
+      |                ~~~~~~~~
+    3 |     Int
+    4 | }
+vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv:3:2: error: cannot embed non-struct `Int`
+    1 | type Int = int
+    2 | type MyIndex = struct {
+    3 |     Int
+      |     ~~~
+    4 | }
diff --git a/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv b/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv
new file mode 100644
index 000000000..885a2c3c1
--- /dev/null
+++ b/vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.vv
@@ -0,0 +1,4 @@
+type Int = int
+type MyIndex = struct {
+	Int
+}
diff --git a/vlib/v/parser/tests/struct_anon_invalid_embed_err.out b/vlib/v/parser/tests/struct_anon_invalid_embed_err.out
new file mode 100644
index 000000000..8e59b9a3d
--- /dev/null
+++ b/vlib/v/parser/tests/struct_anon_invalid_embed_err.out
@@ -0,0 +1,6 @@
+vlib/v/parser/tests/struct_anon_invalid_embed_err.vv:3:6: error: cannot embed non-struct `Int`
+    1 | type Int = int
+    2 | type MyIndex = struct {
+    3 |     Int Int
+      |         ~~~
+    4 | }
diff --git a/vlib/v/parser/tests/struct_anon_invalid_embed_err.vv b/vlib/v/parser/tests/struct_anon_invalid_embed_err.vv
new file mode 100644
index 000000000..a8ceda30e
--- /dev/null
+++ b/vlib/v/parser/tests/struct_anon_invalid_embed_err.vv
@@ -0,0 +1,4 @@
+type Int = int
+type MyIndex = struct {
+	Int Int
+}
-- 
2.39.5