From b20e78d5f66d19bb142f3690b2a8c0b861bb91e1 Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@ucc.asn.au>
Date: Fri, 23 Aug 2019 20:52:58 +0800
Subject: MIR Optimise - Handle case where a &mut isn't used

---
 src/mir/optimise.cpp | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src')

diff --git a/src/mir/optimise.cpp b/src/mir/optimise.cpp
index 2d4dbc68..183894c5 100644
--- a/src/mir/optimise.cpp
+++ b/src/mir/optimise.cpp
@@ -1878,6 +1878,11 @@ bool MIR_Optimise_DeTemporary_Borrows(::MIR::TypeResolve& state, ::MIR::Function
             //DEBUG(this_var << " - Multi-assign, or use-by-value");
             continue ;
         }
+        if( slot.n_deref_read == 0 )
+        {
+            //DEBUG(this_var << " - Not used");
+            continue ;
+        }
 
         // Check that the source was a borrow statement
         auto& src_bb = fcn.blocks[slot.set_loc.bb_idx];
-- 
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