ast, checker, cgen: fix nested struct embed error (fix #12659) (#12712)

cmd/tools/vast/vast.v

@@ -1345,7 +1345,7 @@ fn (t Tree) selector_expr(node ast.SelectorExpr) &Node {
 	obj.add('typ', t.type_node(node.typ))
 	obj.add('name_type', t.type_node(node.name_type))
 	obj.add('gkind_field', t.enum_node(node.gkind_field))
-	obj.add('from_embed_type', t.type_node(node.from_embed_type))
+	obj.add('from_embed_types', t.array_node_type(node.from_embed_types))
 	obj.add('next_token', t.token_node(node.next_token))
 	obj.add('pos', t.position(node.pos))
 	obj.add('scope', t.number_node(int(node.scope)))

vlib/v/ast/ast.v

@@ -229,7 +229,7 @@ pub mut:
 	name_type        Type // T in `T.name` or typeof in `typeof(expr).name`
 	gkind_field      GenericKindField // `T.name` => ast.GenericKindField.name, `T.typ` => ast.GenericKindField.typ, or .unknown
 	scope            &Scope
-	from_embed_type Type // holds the type of the embed that the method is called from
+	from_embed_types []Type // holds the type of the embed that the method is called from
 }
 
 // root_ident returns the origin ident where the selector started.

vlib/v/ast/table.v

@@ -503,22 +503,23 @@ pub fn (t &Table) find_field(s &TypeSymbol, name string) ?StructField {
 pub fn (t &Table) find_field_from_embeds_recursive(sym &TypeSymbol, field_name string) ?(StructField, []Type) {
 	if sym.info is Struct {
 		mut found_fields := []StructField{}
-		mut embeds_of_found_fields := [][]Type{}
+		mut embeds_of_found_fields := []Type{}
 		for embed in sym.info.embeds {
 			embed_sym := t.get_type_symbol(embed)
 			if field := t.find_field(embed_sym, field_name) {
 				found_fields << field
-				embeds_of_found_fields << [embed]
+				embeds_of_found_fields << embed
 			} else {
 				field, types := t.find_field_from_embeds_recursive(embed_sym, field_name) or {
-					StructField{}, []Type{}
+					continue
 				}
 				found_fields << field
+				embeds_of_found_fields << embed
 				embeds_of_found_fields << types
 			}
 		}
 		if found_fields.len == 1 {
-			return found_fields[0], embeds_of_found_fields[0]
+			return found_fields[0], embeds_of_found_fields
 		} else if found_fields.len > 1 {
 			return error('ambiguous field `$field_name`')
 		}
@@ -526,7 +527,7 @@ pub fn (t &Table) find_field_from_embeds_recursive(sym &TypeSymbol, field_name s
 		for typ in sym.info.types {
 			agg_sym := t.get_type_symbol(typ)
 			field, embed_types := t.find_field_from_embeds_recursive(agg_sym, field_name) or {
-				return err
+				continue
 			}
 			if embed_types.len > 0 {
 				return field, embed_types
@@ -578,7 +579,7 @@ pub fn (t &Table) find_field_with_embeds(sym &TypeSymbol, field_name string) ?St
 	} else {
 		// look for embedded field
 		first_err := err
-		field, _ := t.find_field_from_embeds(sym, field_name) or { return first_err }
+		field, _ := t.find_field_from_embeds_recursive(sym, field_name) or { return first_err }
 		return field
 	}
 }

vlib/v/checker/checker.v

@@ -3460,15 +3460,15 @@ pub fn (mut c Checker) selector_expr(mut node ast.SelectorExpr) ast.Type {
 		} else {
 			// look for embedded field
 			has_field = true
-			mut embed_type := ast.Type(0)
-			field, embed_type = c.table.find_field_from_embeds(sym, field_name) or {
+			mut embed_types := []ast.Type{}
+			field, embed_types = c.table.find_field_from_embeds_recursive(sym, field_name) or {
 				if err.msg != '' {
 					c.error(err.msg, node.pos)
 				}
 				has_field = false
-				ast.StructField{}, ast.Type(0)
+				ast.StructField{}, []ast.Type{}
 			}
-			node.from_embed_type = embed_type
+			node.from_embed_types = embed_types
 			if sym.kind in [.aggregate, .sum_type] {
 				unknown_field_msg = err.msg
 			}
@@ -3489,15 +3489,15 @@ pub fn (mut c Checker) selector_expr(mut node ast.SelectorExpr) ast.Type {
 			} else {
 				// look for embedded field
 				has_field = true
-				mut embed_type := ast.Type(0)
-				field, embed_type = c.table.find_field_from_embeds(gs, field_name) or {
+				mut embed_types := []ast.Type{}
+				field, embed_types = c.table.find_field_from_embeds_recursive(gs, field_name) or {
 					if err.msg != '' {
 						c.error(err.msg, node.pos)
 					}
 					has_field = false
-					ast.StructField{}, ast.Type(0)
+					ast.StructField{}, []ast.Type{}
 				}
-				node.from_embed_type = embed_type
+				node.from_embed_types = embed_types
 			}
 		}
 	}

vlib/v/gen/c/cgen.v

@@ -4226,8 +4226,8 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 	}
 	// struct embedding
 	if sym.info in [ast.Struct, ast.Aggregate] {
-		if node.from_embed_type != 0 {
-			embed_sym := g.table.get_type_symbol(node.from_embed_type)
+		for embed in node.from_embed_types {
+			embed_sym := g.table.get_type_symbol(embed)
 			embed_name := embed_sym.embed_name()
 			if node.expr_type.is_ptr() {
 				g.write('->')
@@ -4237,7 +4237,7 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 			g.write(embed_name)
 		}
 	}
-	if (node.expr_type.is_ptr() || sym.kind == .chan) && node.from_embed_type == 0 {
+	if (node.expr_type.is_ptr() || sym.kind == .chan) && node.from_embed_types.len == 0 {
 		g.write('->')
 	} else {
 		// g.write('. /*typ=  $it.expr_type */') // ${g.typ(it.expr_type)} /')

vlib/v/tests/nested_struct_embed_test.v

@@ -0,0 +1,20 @@
+struct Foo {
+mut:
+	x int
+}
+
+struct Bar {
+	Foo
+}
+
+struct Baz {
+	Bar
+}
+
+fn test_nested_struct_embed() {
+	mut baz := Baz{}
+	baz.x = 3
+
+	println(baz.x)
+	assert baz.x == 3
+}