[Version 10.0] Feature support for file-scoped namespaces#1540
Draft
RexJaeschke wants to merge 4 commits into
Draft
[Version 10.0] Feature support for file-scoped namespaces#1540RexJaeschke wants to merge 4 commits into
RexJaeschke wants to merge 4 commits into
Conversation
RexJaeschke
added
type: feature
RexJaeschke
marked this pull request as draft
January 22, 2026 17:39
RexJaeschke
commented
Jan 22, 2026
Comment on lines
+776
to
+777
| - The scope of a name defined by an *extern_alias_directive* ([§14.4](namespaces.md#144-extern-alias-directives)) extends over the *using_directive*s, *global_attributes*, and *compilation_unit_body* of its immediately containing *compilation_unit* or *namespace_body*. An *extern_alias_directive* does not contribute any new members to the underlying declaration space. In other words, an *extern_alias_directive* is not transitive, but, rather, affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs. | ||
| - The scope of a name defined or imported by a *using_directive* ([§14.5](namespaces.md#145-using-directives)) extends over the *global_attributes* and *compilation_unit_body* of the *compilation_unit* or *namespace_body* in which the *using_directive* occurs. A *using_directive* may make zero or more namespace or type names available within a particular *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* but does not contribute any new members to the underlying declaration space. In other words, a *using_directive* is not transitive but rather affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs. |
Contributor
Author
There was a problem hiding this comment.
I expect that eventually there will be a conflict generated by these bullet items. These edits are built on top of the edits for the V9 feature "Top-Level Statements" (see PR #1454). And just an hour ago, I tweaked that PR to include "statement_lists" in two places in these items. Ultimately, this PR will need to remove those bits of text as their inclusion is subsumed by this PR.
RexJaeschke
commented
Jan 22, 2026
| ``` | ||
|
|
||
| The scope of an *extern_alias_directive* extends over the *using_directive*s, *global_attributes* and *namespace_member_declaration*s of its immediately containing *compilation_unit* or *namespace_body*. | ||
| The scope of an *extern_alias_directive* is described in [§7.7.1]( basic-concepts.md#771-general). |
Contributor
Author
There was a problem hiding this comment.
Here, I invoked the spec-writing rule, "Don't say the same thing in two different places!"
RexJaeschke
commented
Jan 22, 2026
| A *using_static_directive* ([§14.5.4](namespaces.md#1454-using-static-directives)) imports the nested types and static members of a type. | ||
|
|
||
| The scope of a *using_directive* extends over the *namespace_member_declarations* of its immediately containing compilation unit or namespace body. The scope of a *using_directive* specifically does not include its peer *using_directive*s. Thus, peer *using_directive*s do not affect each other, and the order in which they are written is insignificant. In contrast, the scope of an *extern_alias_directive* includes the *using_directive*s defined in the same compilation unit or namespace body. | ||
| The scope of a *using_directive* is described in [§7.7.1]( basic-concepts.md#771-general). |
Contributor
Author
There was a problem hiding this comment.
Here, I invoked the spec-writing rule, "Don't say the same thing in two different places!"
BillWagner
force-pushed
the
v10-file-scoped-namespaces
branch
from
March 20, 2026 17:52
59ede4c to
16264b8
Compare
BillWagner
force-pushed
the
v10-file-scoped-namespaces
branch
from
April 14, 2026 20:16
16264b8 to
213d033
Compare
BillWagner
added a commit
that referenced
this pull request
Apr 15, 2026
BillWagner
force-pushed
the
v10-file-scoped-namespaces
branch
from
May 13, 2026 14:38
213d033 to
47f222d
Compare
BillWagner
force-pushed
the
v10-file-scoped-namespaces
branch
from
June 24, 2026 19:01
47f222d to
0c95845
Compare
Member
|
An earlier version of this feature is already present on |
A few places that referenced namespace declarations didn't include the grammar production for *file_scoped_namespace_declaration* as well as *namespace_body*.
BillWagner
force-pushed
the
v10-file-scoped-namespaces
branch
from
July 24, 2026 19:56
0c95845 to
9174098
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This is Rex's adaptation of the corresponding MS proposal.
This feature allows
as an abbreviation for
As we now have two ways to declare a namespace, different compilation units can use different ways of declaring the same namespace, and we have to make sure the spec allows this. I've attempted to do that, but please read my edits carefully.
Also, I have introduced the grammar rule compilation_unit_body and I have attempted to use it instead of older text, but it's possible it could be used in more cases to make things simpler.