ast, checker, cgen: fix nested struct embed method call (#12714)

Author: yuyi98

cmd/tools/vast/vast.v

@@ -1456,7 +1456,7 @@ fn (t Tree) call_expr(node ast.CallExpr) &Node {
 	obj.add('concrete_types', t.array_node_type(node.concrete_types))
 	obj.add('or_block', t.or_expr(node.or_block))
 	obj.add('concrete_list_pos', t.position(node.concrete_list_pos))
-	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('comments', t.array_node_comment(node.comments))
 	obj.add('pos', t.position(node.pos))
 	obj.add('name_pos', t.position(node.name_pos))

vlib/v/ast/ast.v

@@ -529,7 +529,7 @@ pub mut:
 	concrete_list_pos  token.Position
 	free_receiver      bool // true if the receiver expression needs to be freed
 	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
 	comments           []Comment
 }
 

vlib/v/ast/table.v

@@ -409,6 +409,43 @@ pub fn (t &Table) type_find_method_from_embeds(sym &TypeSymbol, method_name stri
 	return none
 }
 
+pub fn (t &Table) type_find_method_from_embeds_recursive(sym &TypeSymbol, method_name string) ?(Fn, []Type) {
+	if sym.info is Struct {
+		mut found_methods := []Fn{}
+		mut embed_of_found_methods := []Type{}
+		for embed in sym.info.embeds {
+			embed_sym := t.get_type_symbol(embed)
+			if m := t.type_find_method(embed_sym, method_name) {
+				found_methods << m
+				embed_of_found_methods << embed
+			} else {
+				method, types := t.type_find_method_from_embeds_recursive(embed_sym, method_name) or {
+					continue
+				}
+				found_methods << method
+				embed_of_found_methods << embed
+				embed_of_found_methods << types
+			}
+		}
+		if found_methods.len == 1 {
+			return found_methods[0], embed_of_found_methods
+		} else if found_methods.len > 1 {
+			return error('ambiguous method `$method_name`')
+		}
+	} else if sym.info is Aggregate {
+		for typ in sym.info.types {
+			agg_sym := t.get_type_symbol(typ)
+			method, embed_types := t.type_find_method_from_embeds_recursive(agg_sym, method_name) or {
+				continue
+			}
+			if embed_types.len != 0 {
+				return method, embed_types
+			}
+		}
+	}
+	return none
+}
+
 fn (t &Table) register_aggregate_field(mut sym TypeSymbol, name string) ?StructField {
 	if sym.kind != .aggregate {
 		t.panic('Unexpected type symbol: $sym.kind')

vlib/v/checker/checker.v

@@ -2083,17 +2083,18 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 		}
 		if !has_method {
 			has_method = true
-			mut embed_type := ast.Type(0)
-			method, embed_type = c.table.type_find_method_from_embeds(left_sym, method_name) or {
+			mut embed_types := []ast.Type{}
+			method, embed_types = c.table.type_find_method_from_embeds_recursive(left_sym,
+				method_name) or {
 				if err.msg != '' {
 					c.error(err.msg, node.pos)
 				}
 				has_method = false
-				ast.Fn{}, ast.Type(0)
+				ast.Fn{}, []ast.Type{}
 			}
-			if embed_type != 0 {
+			if embed_types.len != 0 {
 				is_method_from_embed = true
-				node.from_embed_type = embed_type
+				node.from_embed_types = embed_types
 			}
 		}
 		if left_sym.kind == .aggregate {
@@ -2262,7 +2263,7 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 			}
 		}
 		if is_method_from_embed {
-			node.receiver_type = node.from_embed_type.derive(method.params[0].typ)
+			node.receiver_type = node.from_embed_types.last().derive(method.params[0].typ)
 		} else if is_generic {
 			// We need the receiver to be T in cgen.
 			// TODO: cant we just set all these to the concrete type in checker? then no need in gen

vlib/v/gen/c/fn.v

@@ -946,7 +946,7 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 	}
 	if node.receiver_type.is_ptr()
 		&& (!node.left_type.is_ptr() || node.left_type.has_flag(.variadic)
-		|| node.from_embed_type != 0
+		|| node.from_embed_types.len != 0
 		|| (node.left_type.has_flag(.shared_f) && node.name != 'str')) {
 		// The receiver is a reference, but the caller provided a value
 		// Add `&` automatically.
@@ -960,11 +960,11 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 			}
 		}
 	} else if !node.receiver_type.is_ptr() && node.left_type.is_ptr() && node.name != 'str'
-		&& node.from_embed_type == 0 {
+		&& node.from_embed_types.len == 0 {
 		if !node.left_type.has_flag(.shared_f) {
 			g.write('/*rec*/*')
 		}
-	} else if !is_range_slice && node.from_embed_type == 0 && node.name != 'str' {
+	} else if !is_range_slice && node.from_embed_types.len == 0 && node.name != 'str' {
 		diff := node.left_type.nr_muls() - node.receiver_type.nr_muls()
 		if diff < 0 {
 			// TODO
@@ -996,8 +996,9 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 		} else {
 			g.expr(node.left)
 		}
-		if node.from_embed_type != 0 {
-			embed_name := typ_sym.embed_name()
+		for embed in node.from_embed_types {
+			embed_sym := g.table.get_type_symbol(embed)
+			embed_name := embed_sym.embed_name()
 			if node.left_type.is_ptr() {
 				g.write('->')
 			} else {

vlib/v/tests/nested_struct_embed_method_call_test.v

@@ -0,0 +1,22 @@
+struct Foo1 {
+	x int
+}
+
+struct Foo2 {
+	Foo1
+}
+
+struct Foo3 {
+	Foo2
+}
+
+fn (f Foo1) bar() string {
+	println('Foo1.bar()')
+	return 'Foo1.bar()'
+}
+
+fn test_nested_struct_embed_method_call() {
+	f3 := Foo3{}
+	ret := f3.bar()
+	assert ret == 'Foo1.bar()'
+}