Nope, because you can have arbitrary constant expressions within template instantiations. foo<bar<1> could be interpreted as "foo<(bar < 1)>" or "foo < bar<1>"

Nope, because you can have arbitrary constant expressions within template instantiations. foo<bar<1> could be interpreted as "foo<(bar < 1)>" or "foo < bar<1>" It's undecidable without symbol lookup.