From 440212a154ba26a633fa1360ed1f7bb29b274026 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oscar=20Nihlg=C3=A5rd?= <oscarnihlgard@gmail.com>
Date: Mon, 4 Jun 2018 13:38:26 +0200
Subject: [PATCH] Fix for newStringOfCap in VM (#7901)

---
 compiler/vmgen.nim   | 3 ++-
 tests/vm/tvmmisc.nim | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 7ac3b5cf75..8a3c7e2e6e 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -844,7 +844,8 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
   of mNewStringOfCap:
     # we ignore the 'cap' argument and translate it as 'newString(0)'.
     # eval n.sons[1] for possible side effects:
-    var tmp = c.genx(n.sons[1])
+    c.freeTemp(c.genx(n.sons[1]))
+    var tmp = c.getTemp(n.sons[1].typ)
     c.gABx(n, opcLdImmInt, tmp, 0)
     if dest < 0: dest = c.getTemp(n.typ)
     c.gABC(n, opcNewStr, dest, tmp)
diff --git a/tests/vm/tvmmisc.nim b/tests/vm/tvmmisc.nim
index 472660bc22..4af824cf47 100644
--- a/tests/vm/tvmmisc.nim
+++ b/tests/vm/tvmmisc.nim
@@ -82,3 +82,11 @@ block:
 
     assert fileExists("MISSINGFILE") == false
     assert dirExists("MISSINGDIR") == false
+
+# #7210
+block:
+  static:
+    proc f(size: int): int =
+      var some = newStringOfCap(size)
+      result = size
+    doAssert f(4) == 4
\ No newline at end of file