fixups: split out throwing deallocation function ub

Author: joshuaberne

source/basic.tex

@@ -4423,7 +4423,7 @@
 signature.
 
 \pnum
-If a deallocation function terminates by throwing an exception, the behavior is undefined.\ubxref{basic.stc.alloc.dealloc.constraint.2}
+If a deallocation function terminates by throwing an exception, the behavior is undefined.\ubxref{basic.stc.alloc.dealloc.throw}
 The value of the first argument supplied to a deallocation function may
 be a null pointer value; if so, and if the deallocation function is one
 supplied in the standard library, the call has no effect.

source/ub.tex

@@ -262,11 +262,9 @@
 
 \pnum
 \ubxref{basic.stc.alloc.dealloc.constraint} \\
-% \ubxref{basic.stc.alloc.dealloc.constraint.2} \\
 If the behavior of an allocation or deallocation function does not satisfy the semantic constraints
 specified
-in \iref{basic.stc.dynamic.allocation} and \iref{basic.stc.dynamic.deallocation},
-including exiting via a thrown exception when not specified to do so,
+in \iref{basic.stc.dynamic.allocation} and \iref{basic.stc.dynamic.deallocation}.
 the behavior is undefined.
 
 
@@ -287,6 +285,27 @@
 \end{codeblock}
 \end{example}
 
+\pnum
+\ubxref{basic.stc.alloc.dealloc.throw} \\
+If a call to a deallocation function
+terminates by throwing an exception
+the behavior is undefined.
+\pnum
+\begin{example}
+\begin{codeblock}
+struct X {
+  void operator delete(void*) { throw "oops"; }
+};
+void f()
+{
+  X* x = new X();
+  delete x;  // undefined behavior
+}
+\end{codeblock}
+\end{example}
+
+
+
 \rSec2[ub.basic.stc.alloc.zero.dereference]{Zero-sized allocation dereference}
 
 \pnum