Rationale (October, 2004):

CWG felt that readers might misunderstand “declaration” as meaning “non-definition declaration.”

Notes from the March 2004 meeting:

Jens Maurer prepared drafting for this issue, but we find ourselves reluctant to actually make the changes. Though correct, they seemed more likely to be misread than the existing wording.

Proposed resolution:

Remove in Clause 3 [intro.defs] “parameter” the indicated words:

an object or reference declared as part of a function declaration or definition, or in the catch clause of an exception handler, that acquires a value on entry to the function or handler; ...

Remove in 13.2 [temp.param] paragraph 10 the indicated words:

The set of default template-arguments available for use with a template declaration or definition is obtained by merging the default arguments from the definition (if in scope) and all declarations in scope in the same way default function arguments are (...).

Remove in 13.8 [temp.res] paragraph 2 the indicated words:

A name used in a template declaration or definition and that is dependent on a template-parameter is assumed not to name a type unless the applicable name lookup finds a type name or the name is qualified by the keyword typename.

Remove in 13.8.4.1 [temp.point] paragraph 1 the indicated words:

Otherwise, the point of instantiation for such a specialization immediately follows the namespace scope declaration or definition that refers to the specialization.

Remove in 13.8.4.1 [temp.point] paragraph 3 the indicated words:

Otherwise, the point of instantiation for such a specialization immediately precedes the namespace scope declaration or definition that refers to the specialization.

Remove in 13.9.4 [temp.expl.spec] paragraph 21 the indicated words:

Default function arguments shall not be specified in a declaration or a definition for one of the following explicit specializations:

• ...

[Note: default function arguments may be specified in the declaration or definition of a member function of a class template specialization that is explicitly specialized. ]

Remove in 13.10.3.6 [temp.deduct.type] paragraph 18 the indicated words:

[Note: a default template-argument cannot be specified in a function template declaration or definition; ...]

Remove in 16.4.3.2 [using.headers] paragraph 3 the indicated words:

A translation unit shall include a header only outside of any external declaration or definition, and shall include the header lexically before the first reference to any of the entities it declares or first defines in that translation unit.

Because a definition is also a declaration, it might make sense to change uses of "declaration or definition" to simply "declaration".