Fix some random -Wconversion warnings

1 files changed, 5 insertions, 3 deletions

diff --git a/src/libexpr/attr-set.cc b/src/libexpr/attr-set.cc
index b284daa3c2f7..0474865c6d7d 100644
--- a/src/libexpr/attr-set.cc
+++ b/src/libexpr/attr-set.cc
@@ -24,13 +24,15 @@ static void * allocBytes(size_t n)
 /* Allocate a new array of attributes for an attribute set with a specific
    capacity. The space is implicitly reserved after the Bindings
    structure. */
-Bindings * EvalState::allocBindings(Bindings::size_t capacity)
+Bindings * EvalState::allocBindings(size_t capacity)
 {
-    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings(capacity);
+    if (capacity > std::numeric_limits<Bindings::size_t>::max())
+        throw Error("attribute set of size %d is too big", capacity);
+    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings((Bindings::size_t) capacity);
 }
 
 
-void EvalState::mkAttrs(Value & v, unsigned int capacity)
+void EvalState::mkAttrs(Value & v, size_t capacity)
 {
     if (capacity == 0) {
         v = vEmptySet;