Implement LWG 2806, Base class of bad_optional_access.

* include/std/optional (bad_optional_access):
Derive from std::exception.
(bad_optional_access::bad_optional_access): Adjust.
(bad_optional_access::what): New.
(__throw_bad_optional_access(const char*)):
Remove the parameter and adjust calls.
* testsuite/20_util/optional/cons/value_neg.cc: Adjust.
* testsuite/20_util/optional/typedefs.cc: Likewise.

From-SVN: r246103

libstdc++-v3/ChangeLog

+2017-03-13  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	Implement LWG 2806, Base class of bad_optional_access.
+	* include/std/optional (bad_optional_access):
+	Derive from std::exception.
+	(bad_optional_access::bad_optional_access): Adjust.
+	(bad_optional_access::what): New.
+	(__throw_bad_optional_access(const char*)):
+	Remove the parameter and adjust calls.
+	* testsuite/20_util/optional/cons/value_neg.cc: Adjust.
+	* testsuite/20_util/optional/typedefs.cc: Likewise.
+
 2017-03-12  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	Implement LWG 2934, optional<const T> doesn't compare with T.

libstdc++-v3/include/std/optional

@@ -76,25 +76,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  dereferenced.
    *  @ingroup exceptions
    */
-  class bad_optional_access : public logic_error
+  class bad_optional_access : public exception
   {
-    // XXX See LEWG 72, https://issues.isocpp.org/show_bug.cgi?id=72
   public:
-    bad_optional_access() : logic_error("bad optional access") { }
-    // XXX This constructor is non-standard. Should not be inline
-    explicit bad_optional_access(const char* __arg) : logic_error(__arg) { }
+    bad_optional_access() { }
+    virtual const char* what() const noexcept override
+    {return "bad optional access";}
 
     virtual ~bad_optional_access() noexcept = default;
   };
 
   void
-  __throw_bad_optional_access(const char*)
+  __throw_bad_optional_access()
   __attribute__((__noreturn__));
 
   // XXX Does not belong here.
   inline void
-  __throw_bad_optional_access(const char* __s)
-  { _GLIBCXX_THROW_OR_ABORT(bad_optional_access(__s)); }
+  __throw_bad_optional_access()
+  { _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
 
   /**
     * @brief Class template that holds the necessary state for @ref optional
@@ -669,8 +668,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       {
 	return this->_M_is_engaged()
 	  ?  this->_M_get()
-	  : (__throw_bad_optional_access("Attempt to access value of a "
-		                         "disengaged optional object"),
+	  : (__throw_bad_optional_access(),
 	     this->_M_get());
       }
 
@@ -679,8 +677,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       {
 	return this->_M_is_engaged()
 	  ?  this->_M_get()
-	  : (__throw_bad_optional_access("Attempt to access value of a "
-		                         "disengaged optional object"),
+	  : (__throw_bad_optional_access(),
 	     this->_M_get());
       }
 
@@ -689,8 +686,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       {
 	return this->_M_is_engaged()
 	  ?  std::move(this->_M_get())
-	  : (__throw_bad_optional_access("Attempt to access value of a "
-		                         "disengaged optional object"),
+	  : (__throw_bad_optional_access(),
 	     std::move(this->_M_get()));
       }
 
@@ -699,8 +695,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       {
 	return this->_M_is_engaged()
 	  ?  std::move(this->_M_get())
-	  : (__throw_bad_optional_access("Attempt to access value of a "
-		                         "disengaged optional object"),
+	  : (__throw_bad_optional_access(),
 	     std::move(this->_M_get()));
       }
 

libstdc++-v3/testsuite/20_util/optional/cons/value_neg.cc

@@ -37,8 +37,8 @@ int main()
     std::optional<std::unique_ptr<int>> oup2 = new int;  // { dg-error "conversion" }
     struct U { explicit U(std::in_place_t); };
     std::optional<U> ou(std::in_place); // { dg-error "no matching" }
-    // { dg-error "no type" "" { target { *-*-* } } 438 }
-    // { dg-error "no type" "" { target { *-*-* } } 448 }
-    // { dg-error "no type" "" { target { *-*-* } } 505 }
+    // { dg-error "no type" "" { target { *-*-* } } 437 }
+    // { dg-error "no type" "" { target { *-*-* } } 447 }
+    // { dg-error "no type" "" { target { *-*-* } } 504 }
   }
 }

libstdc++-v3/testsuite/20_util/optional/typedefs.cc

@@ -29,5 +29,7 @@ using check2_t = std::in_place_t;
 using check3_t = std::nullopt_t;
 using check4_t = std::bad_optional_access;
 
-static_assert(std::is_base_of<std::logic_error, check4_t>::value,
-	      "bad_optional_access must derive from logic_error");
+static_assert(!std::is_base_of<std::logic_error, check4_t>::value,
+	      "bad_optional_access must derive from exception");
+static_assert(std::is_base_of<std::exception, check4_t>::value,
+	      "bad_optional_access must derive from exception");