Allow for-loops to define local variables

parse.c

@@ -577,7 +577,14 @@ static Node *stmt(Token **rest, Token *tok) {
     Node *node = new_node(ND_FOR, tok);
     tok = skip(tok->next, "(");
 
-    node->init = expr_stmt(&tok, tok);
+    enter_scope();
+
+    if (is_typename(tok)) {
+      Type *basety = declspec(&tok, tok, NULL);
+      node->init = declaration(&tok, tok, basety);
+    } else {
+      node->init = expr_stmt(&tok, tok);
+    }
 
     if (!equal(tok, ";"))
       node->cond = expr(&tok, tok);
@@ -588,6 +595,7 @@ static Node *stmt(Token **rest, Token *tok) {
     tok = skip(tok, ")");
 
     node->then = stmt(rest, tok);
+    leave_scope();
     return node;
   }
 

test/control.c

@@ -24,6 +24,9 @@ int main() {
   ASSERT(5, ({ int i=2, j=3; (i=5,j)=6; i; }));
   ASSERT(6, ({ int i=2, j=3; (i=5,j)=6; j; }));
 
+  ASSERT(55, ({ int j=0; for (int i=0; i<=10; i=i+1) j=j+i; j; }));
+  ASSERT(3, ({ int i=3; int j=0; for (int i=0; i<=10; i=i+1) j=j+i; i; }));
+
   printf("OK\n");
   return 0;
 }