parser, checker: improve checks for embed in anon struct

vlib/v/checker/checker.v

@@ -561,6 +561,13 @@ fn (mut c Checker) alias_type_decl(node ast.AliasTypeDecl) {
 						c.error('unknown type `${ct_sym.name}`', node.type_pos)
 					}
 				}
+				for embed_type in parent_typ_sym.info.embeds {
+					final_embed_sym := c.table.final_sym(embed_type)
+					if final_embed_sym.kind != .struct_ {
+						c.error('cannot embed non-struct `${c.table.sym(embed_type).name}`',
+							node.type_pos)
+					}
+				}
 			}
 		}
 		.array {

vlib/v/checker/tests/type_alias_decl_anon_struct_invalid_embed.out

@@ -0,0 +1,6 @@
+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

@@ -0,0 +1,4 @@
+type Int = int
+type MyIndex = struct {
+	Int
+}

vlib/v/parser/struct.v

@@ -239,6 +239,9 @@ fn (mut p Parser) struct_decl(is_anon bool) ast.StructDecl {
 					typ = p.table.find_type_idx(p.anon_struct_decl.name)
 				} else {
 					start_type_pos := p.tok.pos()
+					if field_name == p.tok.lit && p.tok.lit[0].is_capital() {
+						p.error('field-name `${p.tok.lit}` cannot be same as the type-name')
+					}
 					typ = p.parse_type()
 					type_pos = start_type_pos.extend(p.prev_tok.pos())
 				}

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: field-name `Int` cannot be same as the type-name
+    1 | type Int = int
+    2 | type MyIndex = struct {
+    3 |     Int Int
+      |         ~~~
+    4 | }

vlib/v/parser/tests/struct_anon_invalid_embed_err.vv

@@ -0,0 +1,4 @@
+type Int = int
+type MyIndex = struct {
+	Int Int
+}