Annex C (informative) Compatibility [diff]

C.4 C++ and ISO C++ 2003 [diff.cpp03]

C.4.6 [temp]: templates [diff.cpp03.temp]

Affected subclause: [temp.param]
Change: Repurpose export for modules ([module], [cpp.module], [cpp.import]).

Rationale: No implementation consensus for the C++ 2003 meaning of export.

Effect on original feature: A valid C++ 2003 program containing export is ill-formed in this revision of C++.
Affected subclause: [temp.arg]
Change: Remove whitespace requirement for nested closing template right angle brackets.

Rationale: Considered a persistent but minor annoyance.
Template aliases representing non-class types would exacerbate whitespace issues.

Effect on original feature: Change to semantics of well-defined expression.
A valid C++ 2003 expression containing a right angle bracket (“>”) followed immediately by another right angle bracket may now be treated as closing two templates.
For example, the following code is valid in C++ 2003 because “>>” is a right-shift operator, but invalid in this revision of C++ because “>>” closes two templates.
template <class T> struct X { }; template <int N> struct Y { }; X< Y< 1 >> 2 > > x;
Affected subclause: [temp.dep.candidate]
Change: Allow dependent calls of functions with internal linkage.

Rationale: Overly constrained, simplify overload resolution rules.

Effect on original feature: A valid C++ 2003 program could get a different result than in this revision of C++.