cgen: fix codegen for multi return with array fixed (fix #22451) (#22454

)

vlib/v/gen/c/assign.v

@@ -910,7 +910,7 @@ fn (mut g Gen) gen_multi_return_assign(node &ast.AssignStmt, return_type ast.Typ
 			}
 		} else {
 			g.expr(lx)
-			sym := g.table.sym(node.left_types[i])
+			sym := g.table.final_sym(node.left_types[i])
 			if sym.kind == .array_fixed {
 				g.writeln(';')
 				g.writeln('memcpy(&${g.expr_string(lx)}, &${mr_var_name}.arg${i}, sizeof(${styp}));')

vlib/v/gen/c/cgen.v

@@ -5504,6 +5504,7 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 		|| g.cur_lock.lockeds.len > 0
 		|| (fn_return_is_multi && node.exprs.len >= 1 && fn_return_is_option)
 		|| fn_return_is_fixed_array
+		|| (fn_return_is_multi && node.types.any(g.table.final_sym(it).kind == .array_fixed))
 	// handle promoting none/error/function returning _option'
 	if fn_return_is_option {
 		option_none := node.exprs[0] is ast.None
@@ -5603,6 +5604,7 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 		}
 		// Use this to keep the tmp assignments in order
 		mut multi_unpack := ''
+		mut final_assignments := ''
 		g.write('(${styp}){')
 		mut arg_idx := 0
 		for i, expr in node.exprs {
@@ -5639,17 +5641,27 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 				continue
 			}
 			g.write('.arg${arg_idx}=')
-			if expr.is_auto_deref_var() {
-				g.write('*')
-			}
-			if mr_info.types[i].has_flag(.option) {
-				g.expr_with_opt(expr, node.types[i], mr_info.types[i])
-			} else if g.table.sym(mr_info.types[i]).kind in [.sum_type, .interface_] {
-				g.expr_with_cast(expr, node.types[i], mr_info.types[i])
-			} else {
+			if expr !is ast.ArrayInit && g.table.final_sym(node.types[i]).kind == .array_fixed {
+				line := g.go_before_last_stmt().trim_space()
+				expr_styp := g.typ(node.types[i])
+				g.write('memcpy(&${tmpvar}.arg${arg_idx}, ')
 				g.expr(expr)
+				g.writeln(', sizeof(${expr_styp}));')
+				final_assignments += g.go_before_last_stmt() + '\t'
+				g.write(line)
+				g.write('{0}')
+			} else {
+				if expr.is_auto_deref_var() {
+					g.write('*')
+				}
+				if mr_info.types[i].has_flag(.option) {
+					g.expr_with_opt(expr, node.types[i], mr_info.types[i])
+				} else if g.table.sym(mr_info.types[i]).kind in [.sum_type, .interface_] {
+					g.expr_with_cast(expr, node.types[i], mr_info.types[i])
+				} else {
+					g.expr(expr)
+				}
 			}
-
 			if i < node.exprs.len - 1 {
 				g.write(', ')
 			}
@@ -5669,6 +5681,10 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 		if multi_unpack != '' {
 			g.insert_before_stmt(multi_unpack)
 		}
+		if final_assignments != '' {
+			g.writeln(';')
+			g.write(final_assignments)
+		}
 		if use_tmp_var && !fn_return_is_option && !fn_return_is_result {
 			if !has_semicolon {
 				g.writeln(';')

vlib/v/tests/fns/multi_return_array_fixed_test.v

@@ -0,0 +1,19 @@
+module main
+
+type Mat4 = [2]f32
+
+struct GameObject {
+mut:
+	rot       Mat4 = Mat4([f32(1.1), 2.2]!)
+	transform Mat4 = Mat4([f32(1.1), 2.2]!)
+}
+
+fn (g GameObject) calc() (Mat4, Mat4) {
+	return g.rot, g.transform
+}
+
+fn test_main() {
+	x, y := GameObject{}.calc()
+	assert x == Mat4([f32(1.1), 2.2]!)
+	assert y == Mat4([f32(1.1), 2.2]!)
+}