class/module body to honor whether value is required or not; reduce a few...

class/module body to honor whether value is required or not; reduce a few instructions for normal cases

src/codegen.c

@@ -657,14 +657,17 @@ lambda_body(codegen_scope *s, node *tree, int blk)
 }
 
 static int
-scope_body(codegen_scope *s, node *tree)
+scope_body(codegen_scope *s, node *tree, int val)
 {
   codegen_scope *scope = scope_new(s->mrb, s, tree->car);
 
-  codegen(scope, tree->cdr, VAL);
+  codegen(scope, tree->cdr, val);
   if (!s->iseq) {
     genop(scope, MKOP_A(OP_STOP, 0));
   }
+  else if (!val) {
+    genop(scope, MKOP_AB(OP_RETURN, 0, OP_R_NORMAL));
+  }
   else {
     if (scope->nregs == 0) {
       genop(scope, MKOP_A(OP_LOADNIL, 0));
@@ -1235,7 +1238,7 @@ codegen(codegen_scope *s, node *tree, int val)
       genop(s, MKOP_Bx(OP_EPUSH, 0));
       s->ensure_level++;
       codegen(s, tree->car, val);
-      idx = scope_body(s, tree->cdr);
+      idx = scope_body(s, tree->cdr, NOVAL);
       s->iseq[epush] = MKOP_Bx(OP_EPUSH, idx);
       s->ensure_level--;
       genop_peep(s, MKOP_A(OP_EPOP, 1), NOVAL);
@@ -1420,7 +1423,7 @@ codegen(codegen_scope *s, node *tree, int val)
     break;
 
   case NODE_SCOPE:
-    scope_body(s, tree);
+    scope_body(s, tree, NOVAL);
     break;
 
   case NODE_FCALL:
@@ -2280,7 +2283,7 @@ codegen(codegen_scope *s, node *tree, int val)
       pop(); pop();
       idx = new_msym(s, sym(tree->car->cdr));
       genop(s, MKOP_AB(OP_CLASS, cursp(), idx));
-      idx = scope_body(s, tree->cdr->cdr->car);
+      idx = scope_body(s, tree->cdr->cdr->car, val);
       genop(s, MKOP_ABx(OP_EXEC, cursp(), idx));
       if (val) {
         push();
@@ -2306,7 +2309,7 @@ codegen(codegen_scope *s, node *tree, int val)
       pop();
       idx = new_msym(s, sym(tree->car->cdr));
       genop(s, MKOP_AB(OP_MODULE, cursp(), idx));
-      idx = scope_body(s, tree->cdr->car);
+      idx = scope_body(s, tree->cdr->car, val);
       genop(s, MKOP_ABx(OP_EXEC, cursp(), idx));
       if (val) {
         push();
@@ -2321,7 +2324,7 @@ codegen(codegen_scope *s, node *tree, int val)
       codegen(s, tree->car, VAL);
       pop();
       genop(s, MKOP_AB(OP_SCLASS, cursp(), cursp()));
-      idx = scope_body(s, tree->cdr->car);
+      idx = scope_body(s, tree->cdr->car, val);
       genop(s, MKOP_ABx(OP_EXEC, cursp(), idx));
       if (val) {
         push();