Fix self value in a block is changed with return value for Fixnum, nil, instance variable.

Fix #1504

src/codegen.c

@@ -278,8 +278,7 @@ genop_peep(codegen_scope *s, mrb_code i, int val)
         s->iseq[s->pc-1] = MKOP_AB(OP_RETURN, GETARG_B(i0), OP_R_NORMAL);
         return;
       case OP_LOADI:
-        s->iseq[s->pc-1] = MKOP_AsBx(OP_LOADI, 0, GETARG_sBx(i0));
-        genop(s, MKOP_AB(OP_RETURN, 0, OP_R_NORMAL));
+        genop(s, MKOP_AB(OP_RETURN, GETARG_A(i0), OP_R_NORMAL));
         return;
       case OP_ARRAY:
       case OP_HASH:
@@ -307,8 +306,8 @@ genop_peep(codegen_scope *s, mrb_code i, int val)
       case OP_GETSPECIAL:
       case OP_LOADL:
       case OP_STRING:
-        s->iseq[s->pc-1] = MKOP_ABx(c0, 0, GETARG_Bx(i0));
-        genop(s, MKOP_AB(OP_RETURN, 0, OP_R_NORMAL));
+        s->iseq[s->pc-1] = MKOP_ABx(c0, GETARG_A(i0), GETARG_Bx(i0));
+        genop(s, MKOP_AB(OP_RETURN, GETARG_A(i0), OP_R_NORMAL));
         return;
       case OP_SCLASS:
         s->iseq[s->pc-1] = MKOP_AB(c0, GETARG_A(i), GETARG_B(i0));
@@ -319,8 +318,7 @@ genop_peep(codegen_scope *s, mrb_code i, int val)
       case OP_LOADT:
       case OP_LOADF:
       case OP_OCLASS:
-        s->iseq[s->pc-1] = MKOP_A(c0, 0);
-        genop(s, MKOP_AB(OP_RETURN, 0, OP_R_NORMAL));
+        genop(s, MKOP_AB(OP_RETURN, GETARG_A(i0), OP_R_NORMAL));
         return;
 #if 0
       case OP_SEND:

test/t/proc.rb

@@ -60,13 +60,34 @@ assert('Proc#return_does_not_break_self') do
     attr_accessor :block
     def initialize
     end
-    def register_block
+    def return_array
       @block = Proc.new { self }
       return []
     end
+    def return_instance_variable
+      @block = Proc.new { self }
+      return @block
+    end
+    def return_const_fixnum
+      @block = Proc.new { self }
+      return 123
+    end
+    def return_nil
+      @block = Proc.new { self }
+      return nil
+    end
   end
 
   c = TestClass.new
-  assert_equal [], c.register_block
+  assert_equal [], c.return_array
+  assert_equal c, c.block.call
+
+  c.return_instance_variable
+  assert_equal c, c.block.call
+
+  assert_equal 123, c.return_const_fixnum
+  assert_equal c, c.block.call
+
+  assert_equal nil, c.return_nil
   assert_equal c, c.block.call
 end