`class`/`module` expression  with empty body should return `nil`
Before:
p(class A end)          #=> A
p(class << self; end)   #=> #<Class:#<Object:0x7fdc3880e420>>
p(module B end)         #=> B
After/Ruby:
p(class A end)          #=> nil
p(class << self; end)   #=> nil
p(module B end)         #=> nil
MODIFY
mrbgems/mruby-compiler/core/codegen.c
mrbgems/mruby-compiler/core/codegen.c
@@ -2806,7 +2806,10 @@ codegen(codegen_scope *s, node *tree, int val)
idx = new_sym(s, nsym(tree->car->cdr));
genop_2(s, OP_CLASS, cursp(), idx);
body = tree->cdr->cdr->car;
- if (!(nint(body->cdr->car) == NODE_BEGIN && body->cdr->cdr == NULL)) {
+ if (nint(body->cdr->car) == NODE_BEGIN && body->cdr->cdr == NULL) {
+ genop_1(s, OP_LOADNIL, cursp());
+ }
+ else {
idx = scope_body(s, body, val);
genop_2(s, OP_EXEC, cursp(), idx);
}
@@ -2834,8 +2837,11 @@ codegen(codegen_scope *s, node *tree, int val)
pop();
idx = new_sym(s, nsym(tree->car->cdr));
genop_2(s, OP_MODULE, cursp(), idx);
- if (!(nint(tree->cdr->car->cdr->car) == NODE_BEGIN &&
- tree->cdr->car->cdr->cdr == NULL)) {
+ if (nint(tree->cdr->car->cdr->car) == NODE_BEGIN &&
+ tree->cdr->car->cdr->cdr == NULL) {
+ genop_1(s, OP_LOADNIL, cursp());
+ }
+ else {
idx = scope_body(s, tree->cdr->car, val);
genop_2(s, OP_EXEC, cursp(), idx);
}
@@ -2852,8 +2858,11 @@ codegen(codegen_scope *s, node *tree, int val)
codegen(s, tree->car, VAL);
pop();
genop_1(s, OP_SCLASS, cursp());
- if (!(nint(tree->cdr->car->cdr->car) == NODE_BEGIN &&
- tree->cdr->car->cdr->cdr == NULL)) {
+ if (nint(tree->cdr->car->cdr->car) == NODE_BEGIN &&
+ tree->cdr->car->cdr->cdr == NULL) {
+ genop_1(s, OP_LOADNIL, cursp());
+ }
+ else {
idx = scope_body(s, tree->cdr->car, val);
genop_2(s, OP_EXEC, cursp(), idx);
}

MODIFY
test/t/class.rb
test/t/class.rb
@@ -236,6 +236,11 @@ assert('class to return the last value') do
assert_equal(m, :m)
end
+assert('class to return nil if body is empty') do
+ assert_nil(class C end)
+ assert_nil(class << self; end)
+end
+
assert('raise when superclass is not a class') do
module FirstModule; end
assert_raise(TypeError, 'should raise TypeError') do

MODIFY
test/t/module.rb
test/t/module.rb
@@ -708,6 +708,15 @@ assert('module with non-class/module outer raises TypeError') do
assert_raise(TypeError) { module []::M2 end }
end
+assert('module to return the last value') do
+ m = module M; :m end
+ assert_equal(m, :m)
+end
+
+assert('module to return nil if body is empty') do
+ assert_nil(module M end)
+end
+
assert('get constant of parent module in singleton class; issue #3568') do
actual = module GetConstantInSingletonTest
EXPECTED = "value"

`class`/`module` expression  with empty body should return `nil`

Before:

  p(class A end)          #=> A
  p(class << self; end)   #=> #<Class:#<Object:0x7fdc3880e420>>
  p(module B end)         #=> B

After/Ruby:

  p(class A end)          #=> nil
  p(class << self; end)   #=> nil
  p(module B end)         #=> nil