bjoernager/rust
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expand: Change how #![cfg(FALSE)] behaves on crate root

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Previously it removed all other attributes from the crate root.
Now it removes only attributes below itself.

So it becomes possible to configure some global crate properties even for fully unconfigured crates.
This commit is contained in:
Vadim Petrochenkov 2023-04-10 14:20:38 +03:00
parent 397641f3bd
commit 46becfdf9c
10 changed files with 63 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

8
compiler/rustc_expand/src/config.rs
View file

@ -197,9 +197,11 @@ pub fn pre_configure_attrs(sess: &Session, attrs: &[Attribute]) -> ast::AttrVec
config_tokens: false,
lint_node_id: ast::CRATE_NODE_ID,
};
let attrs: ast::AttrVec =
attrs.iter().flat_map(|attr| strip_unconfigured.process_cfg_attr(attr)).collect();
if strip_unconfigured.in_cfg(&attrs) { attrs } else { ast::AttrVec::new() }
attrs
.iter()
.flat_map(|attr| strip_unconfigured.process_cfg_attr(attr))
.take_while(|attr| !is_cfg(attr) || strip_unconfigured.cfg_true(attr).0)
.collect()
}
#[macro_export]

20
compiler/rustc_expand/src/expand.rs
View file

@ -1039,7 +1039,12 @@ trait InvocationCollectorNode: HasAttrs + HasNodeId + Sized {
) -> Result<Self::OutputTy, Self> {
Ok(noop_flat_map(node, collector))
}
fn expand_cfg_false(&mut self, collector: &mut InvocationCollector<'_, '_>, span: Span) {
fn expand_cfg_false(
&mut self,
collector: &mut InvocationCollector<'_, '_>,
_pos: usize,
span: Span,
) {
collector.cx.emit_err(RemoveNodeNotSupported { span, descr: Self::descr() });
}
@ -1409,8 +1414,15 @@ impl InvocationCollectorNode for ast::Crate {
fn noop_visit<V: MutVisitor>(&mut self, visitor: &mut V) {
noop_visit_crate(self, visitor)
}
fn expand_cfg_false(&mut self, collector: &mut InvocationCollector<'_, '_>, _span: Span) {
self.attrs.clear();
fn expand_cfg_false(
&mut self,
collector: &mut InvocationCollector<'_, '_>,
pos: usize,
_span: Span,
) {
// Attributes above `cfg(FALSE)` are left in place, because we may want to configure
// some global crate properties even on fully unconfigured crates.
self.attrs.truncate(pos);
// Standard prelude imports are left in the crate for backward compatibility.
self.items.truncate(collector.cx.num_standard_library_imports);
}
@ -1804,7 +1816,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
continue;
}
node.expand_cfg_false(self, span);
node.expand_cfg_false(self, pos, span);
continue;
}
sym::cfg_attr => {