Correctly handle ref variables in an outer frame.

Fixes DMD testcase 'testcontracts'.

gen/dvalue.cpp

@@ -57,6 +57,13 @@ LLValue* DVarValue::getRVal()
     return DtoLoad(tmp);
 }
 
+LLValue* DVarValue::getRefStorage()
+{
+    assert(val);
+    assert(isSpecialRefVar(var));
+    return val;
+}
+
 /////////////////////////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////////////////////////
 

gen/dvalue.h

@@ -110,6 +110,10 @@ struct DVarValue : DValue
     virtual llvm::Value* getLVal();
     virtual llvm::Value* getRVal();
 
+    /// Returns the underlying storage for special internal ref variables.
+    /// Illegal to call on any other value.
+    virtual llvm::Value* getRefStorage();
+
     virtual DVarValue* isVar() { return this; }
 };
 

gen/toir.cpp

@@ -597,12 +597,10 @@ DValue* AssignExp::toElem(IRState* p)
                 // Note that the variable value is accessed directly (instead
                 // of via getLValue(), which would perform a load from the
                 // uninitialized location), and that rhs is stored as an l-value!
-
-                IrLocal* const local = ve->var->ir.irLocal;
-                assert(local && "ref var must be local and already initialized");
-
+                DVarValue* lhs = e1->toElem(p)->isVar();
+                assert(lhs);
                 DValue* rhs = e2->toElem(p);
-                DtoStore(rhs->getLVal(), local->value);
+                DtoStore(rhs->getLVal(), lhs->getRefStorage());
                 return rhs;
             }
         }