Improve spans for auto_cfg(hide/show) errors

Author: GuillaumeGomez

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -504,6 +504,16 @@ pub struct CfgInfo {
     pub value: Option<(Symbol, Span)>,
 }
 
+impl CfgInfo {
+    pub fn span_for_name_and_value(&self) -> Span {
+        if let Some((_, value_span)) = self.value {
+            self.name_span.with_hi(value_span.hi())
+        } else {
+            self.name_span
+        }
+    }
+}
+
 #[derive(Clone, Debug, HashStable_Generic, Encodable, Decodable, PrintAttribute)]
 pub struct CfgHideShow {
     pub kind: HideOrShow,

src/librustdoc/clean/cfg.rs

@@ -47,7 +47,7 @@ fn is_simple_cfg(cfg: &CfgEntry) -> bool {
     }
 }
 
-/// Whether the configuration consists of just `Cfg`, `Not` or `All`.
+/// Returns `false` if is `Any`, otherwise returns `true`.
 fn is_all_cfg(cfg: &CfgEntry) -> bool {
     match cfg {
         CfgEntry::Bool(..)
@@ -756,24 +756,23 @@ fn handle_auto_cfg_hide_show(
     tcx: TyCtxt<'_>,
     cfg_info: &mut CfgInfo,
     attr: &CfgHideShow,
-    attr_span: Span,
     new_show_attrs: &mut FxHashMap<(Symbol, Option<Symbol>), rustc_span::Span>,
     new_hide_attrs: &mut FxHashMap<(Symbol, Option<Symbol>), rustc_span::Span>,
 ) {
     for value in &attr.values {
         let simple = NameValueCfg::from(value);
         if attr.kind == HideOrShow::Show {
             if let Some(span) = new_hide_attrs.get(&(simple.name, simple.value)) {
-                show_hide_show_conflict_error(tcx, attr_span, *span);
+                show_hide_show_conflict_error(tcx, value.span_for_name_and_value(), *span);
             } else {
-                new_show_attrs.insert((simple.name, simple.value), attr_span);
+                new_show_attrs.insert((simple.name, simple.value), value.span_for_name_and_value());
             }
             cfg_info.hidden_cfg.remove(&simple);
         } else {
             if let Some(span) = new_show_attrs.get(&(simple.name, simple.value)) {
-                show_hide_show_conflict_error(tcx, attr_span, *span);
+                show_hide_show_conflict_error(tcx, value.span_for_name_and_value(), *span);
             } else {
-                new_hide_attrs.insert((simple.name, simple.value), attr_span);
+                new_hide_attrs.insert((simple.name, simple.value), value.span_for_name_and_value());
             }
             cfg_info.hidden_cfg.insert(simple);
         }
@@ -871,12 +870,11 @@ pub(crate) fn extract_cfg_from_attrs<'a, I: Iterator<Item = &'a hir::Attribute>
                 ) {
                     return None;
                 }
-                for (value, span) in &d.auto_cfg {
+                for (value, _) in &d.auto_cfg {
                     handle_auto_cfg_hide_show(
                         tcx,
                         cfg_info,
                         value,
-                        *span,
                         &mut new_show_attrs,
                         &mut new_hide_attrs,
                     );

tests/rustdoc-ui/cfg-hide-show-conflict.stderr

@@ -1,14 +1,14 @@
 error: same `cfg` was in `auto_cfg(hide(...))` and `auto_cfg(show(...))` on the same item
-  --> $DIR/cfg-hide-show-conflict.rs:3:8
+  --> $DIR/cfg-hide-show-conflict.rs:3:31
    |
 LL | #![doc(auto_cfg(show(windows, target_os = "linux")))]
-   |        ^^^^^^^^
+   |                               ^^^^^^^^^^^^^^^^^^^
    |
 note: first change was here
-  --> $DIR/cfg-hide-show-conflict.rs:2:8
+  --> $DIR/cfg-hide-show-conflict.rs:2:22
    |
 LL | #![doc(auto_cfg(hide(target_os = "linux")))]
-   |        ^^^^^^^^
+   |                      ^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error