Merge remote-tracking branch 'origin/v90-bugfix'

CHANGELOG

@@ -138,6 +138,7 @@ Interface changes
     `option scip_options 'limits/time 10 display/verblevel 1';`.
   String values should not be quoted and spaces in string values are not supported.
 - sassy can be used now as preprocessor for nauty/traces
+- The solution status codes written to AMPL solution files now match those from https://mp.ampl.com/details.html#_CPPv4N2mp3sol6StatusE.
 
 ### Changed parameters
 

src/amplmp/include/mp/basic-expr-visitor.h

@@ -56,14 +56,16 @@
 
 namespace mp {
 
-// A basic expression visitor that can be used with different expression
-// hierarchies described by ExprTypes.
-//
-// BasicExprVisitor uses the curiously recurring template pattern:
-// http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern
+/// A basic expression visitor that can be used with different expression
+/// hierarchies described by ExprTypes.
+///
+/// BasicExprVisitor uses the curiously recurring template pattern:
+/// http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern
 template <typename Impl, typename Result, typename ExprTypes>
 class BasicExprVisitor {
  public:
+  virtual ~BasicExprVisitor() { }
+
   MP_DEFINE_EXPR_TYPES(ExprTypes);
 
   Result Visit(Expr e);
@@ -181,7 +183,7 @@ class BasicExprVisitor {
     return MP_DISPATCH(VisitUnary(e));
   }
 
-  // Visits a binary expression or a function taking two arguments.
+  /// Visits a binary expression or a function taking two arguments.
   Result VisitBinary(BinaryExpr e) {
     return MP_DISPATCH(VisitNumeric(e));
   }