Make left operand unsigned

Author: Your Name

lib/analyzer.h

@@ -153,13 +153,13 @@ struct Analyzer {
     struct Assume {
         enum Flags : std::uint8_t {
             None = 0,
-            Quiet = (1 << 0),
-            Absolute = (1 << 1),
-            ContainerEmpty = (1 << 2),
+            Quiet = (1u << 0),
+            Absolute = (1u << 1),
+            ContainerEmpty = (1u << 2),
             // The branch this condition guards is not traversed yet (a separate path walks it), so
             // the assume must not record the program state at the branch boundaries - they would be
             // premature. When unset, the branch has been traversed and control is leaving it.
-            Pending = (1 << 3),
+            Pending = (1u << 3),
         };
     };