fix bug in compiler

Author: levno-710

src/prometheus/compiler/compiler.lua

@@ -1729,6 +1729,19 @@ function Compiler:compileStatement(statement, funcDepth)
             self:addStatement(self:setRegister(scope, varRegs[i], Ast.NilExpression()), {varRegs[i]}, {}, false);
         end
 
+        -- Upvalue fix
+        for i, id in ipairs(statement.ids) do
+            if(self:isUpvalue(statement.scope, id)) then
+                local varreg = varRegs[i];
+                local tmpReg = self:allocRegister(false);
+                scope:addReferenceToHigherScope(self.scope, self.allocUpvalFunction);
+                self:addStatement(self:setRegister(scope, tmpReg, Ast.FunctionCallExpression(Ast.VariableExpression(self.scope, self.allocUpvalFunction), {})), {tmpReg}, {}, false);
+                self:addStatement(self:setUpvalueMember(scope, self:register(scope, tmpReg), self:register(scope, varreg)), {}, {tmpReg, varreg}, true);
+                self:addStatement(self:copyRegisters(scope, {varreg}, {tmpReg}), {varreg}, {tmpReg}, false);
+                self:freeRegister(tmpReg, false);
+            end
+        end
+
         self:compileBlock(statement.body, funcDepth);
         self:addStatement(self:setPos(scope, checkBlock.id), {self.POS_REGISTER}, {}, false);
         self:setActiveBlock(finalBlock);