The example demonstrates that

Two expressions involving template parameters are considered equivalent if two function definitions containing the expressions would satisfy the one-definition rule, except that the tokens used to name the template parameters may differ as long as a token used to name a template parameter in one expression is replaced by another token that names the same template parameter in the other expression.

I don't think it's an error.

It seems to me you're taking the text describing example 2, while my proposed change is for example 3 (which is about dependent names). Both examples 2 and 3 contain these exact same lines, and it is correct in example 2, but appears to be copy-paste leftover in example 3.

For determining whether two dependent names\iref{temp.dep} are
equivalent, only the name itself is considered, not the result of name
lookup in the context of the template. If multiple declarations of the
same function template differ in the result of this name lookup, the
result for the first declaration is used.

@jensmaurer, @opensdh: could you kindly take a look? The original wording seems to have been in place since the initial commit.

I agree this repeats parts of the earlier example, but it seems as relevant to the given paragraph ("equivalent") as to the previous one. Maybe the second line of the previous example should actually be removed, because the paragraph specifies that dependent expressions are part of the signature (difference between + and - in the return type), not that template parameter renames are benign.

It's not actually "an exact copy from the previous example": it uses a parameter type instead of a return type. I tend to agree with @jensmaurer that removing the one line from the previous example is a more useful simplification.

@cuzdav: could you make the suggested change, or would you like me to?