Use the right span for errors about #[deprecated] attributes.

Author: m-ou-se

compiler/rustc_attr/src/builtin.rs

@@ -637,19 +637,15 @@ pub struct Deprecation {
 }
 
 /// Finds the deprecation attribute. `None` if none exists.
-pub fn find_deprecation(sess: &Session, attrs: &[Attribute], item_sp: Span) -> Option<Deprecation> {
-    find_deprecation_generic(sess, attrs.iter(), item_sp)
+pub fn find_deprecation(sess: &Session, attrs: &[Attribute]) -> Option<(Deprecation, Span)> {
+    find_deprecation_generic(sess, attrs.iter())
 }
 
-fn find_deprecation_generic<'a, I>(
-    sess: &Session,
-    attrs_iter: I,
-    item_sp: Span,
-) -> Option<Deprecation>
+fn find_deprecation_generic<'a, I>(sess: &Session, attrs_iter: I) -> Option<(Deprecation, Span)>
 where
     I: Iterator<Item = &'a Attribute>,
 {
-    let mut depr: Option<Deprecation> = None;
+    let mut depr: Option<(Deprecation, Span)> = None;
     let diagnostic = &sess.parse_sess.span_diagnostic;
 
     'outer: for attr in attrs_iter {
@@ -658,8 +654,10 @@ where
             continue;
         }
 
-        if depr.is_some() {
-            struct_span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes").emit();
+        if let Some((_, span)) = &depr {
+            struct_span_err!(diagnostic, attr.span, E0550, "multiple deprecated attributes")
+                .span_note(*span, "first deprecation attribute here")
+                .emit();
             break;
         }
 
@@ -780,7 +778,7 @@ where
         sess.mark_attr_used(&attr);
 
         let is_since_rustc_version = sess.check_name(attr, sym::rustc_deprecated);
-        depr = Some(Deprecation { since, note, suggestion, is_since_rustc_version });
+        depr = Some((Deprecation { since, note, suggestion, is_since_rustc_version }, attr.span));
     }
 
     depr

compiler/rustc_expand/src/base.rs

@@ -793,7 +793,7 @@ impl SyntaxExtension {
             allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
             local_inner_macros,
             stability,
-            deprecation: attr::find_deprecation(&sess, attrs, span),
+            deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
             helper_attrs,
             edition,
             is_builtin,

compiler/rustc_passes/src/stability.rs

@@ -85,14 +85,22 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             did_error = self.forbid_staged_api_attrs(hir_id, attrs, inherit_deprecation.clone());
         }
 
-        let depr =
-            if did_error { None } else { attr::find_deprecation(&self.tcx.sess, attrs, item_sp) };
+        let depr = if did_error { None } else { attr::find_deprecation(&self.tcx.sess, attrs) };
         let mut is_deprecated = false;
-        if let Some(depr) = &depr {
+        if let Some((depr, span)) = &depr {
             is_deprecated = true;
 
             if kind == AnnotationKind::Prohibited || kind == AnnotationKind::DeprecationProhibited {
-                self.tcx.sess.span_err(item_sp, "This deprecation annotation is useless");
+                self.tcx
+                    .sess
+                    .struct_span_err(*span, "this deprecation annotation is useless")
+                    .span_suggestion(
+                        *span,
+                        "try removing the deprecation attribute",
+                        String::new(),
+                        rustc_errors::Applicability::MachineApplicable,
+                    )
+                    .emit();
             }
 
             // `Deprecation` is just two pointers, no need to intern it
@@ -116,7 +124,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             }
         } else {
             self.recurse_with_stability_attrs(
-                depr.map(|d| DeprecationEntry::local(d, hir_id)),
+                depr.map(|(d, _)| DeprecationEntry::local(d, hir_id)),
                 None,
                 None,
                 visit_children,
@@ -141,11 +149,11 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             }
         }
 
-        if depr.as_ref().map_or(false, |d| d.is_since_rustc_version) {
+        if let Some((rustc_attr::Deprecation { is_since_rustc_version: true, .. }, span)) = &depr {
             if stab.is_none() {
                 struct_span_err!(
                     self.tcx.sess,
-                    item_sp,
+                    *span,
                     E0549,
                     "rustc_deprecated attribute must be paired with \
                     either stable or unstable attribute"
@@ -168,7 +176,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             // Check if deprecated_since < stable_since. If it is,
             // this is *almost surely* an accident.
             if let (&Some(dep_since), &attr::Stable { since: stab_since }) =
-                (&depr.as_ref().and_then(|d| d.since), &stab.level)
+                (&depr.as_ref().and_then(|(d, _)| d.since), &stab.level)
             {
                 // Explicit version of iter::order::lt to handle parse errors properly
                 for (dep_v, stab_v) in
@@ -214,7 +222,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
         }
 
         self.recurse_with_stability_attrs(
-            depr.map(|d| DeprecationEntry::local(d, hir_id)),
+            depr.map(|(d, _)| DeprecationEntry::local(d, hir_id)),
             stab,
             const_stab,
             visit_children,

src/test/ui/deprecation/deprecation-sanity.rs

@@ -24,8 +24,8 @@ mod bogus_attribute_types_1 {
 }
 
 #[deprecated(since = "a", note = "b")]
-#[deprecated(since = "a", note = "b")]
-fn multiple1() { } //~ ERROR multiple deprecated attributes
+#[deprecated(since = "a", note = "b")] //~ ERROR multiple deprecated attributes
+fn multiple1() { }
 
 #[deprecated(since = "a", since = "b", note = "c")] //~ ERROR multiple 'since' items
 fn f1() { }

src/test/ui/deprecation/deprecation-sanity.stderr

@@ -41,10 +41,16 @@ LL |     #[deprecated("test")]
    |                  ^^^^^^
 
 error[E0550]: multiple deprecated attributes
-  --> $DIR/deprecation-sanity.rs:28:1
+  --> $DIR/deprecation-sanity.rs:27:1
    |
-LL | fn multiple1() { }
-   | ^^^^^^^^^^^^^^^^^^
+LL | #[deprecated(since = "a", note = "b")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: first deprecation attribute here
+  --> $DIR/deprecation-sanity.rs:26:1
+   |
+LL | #[deprecated(since = "a", note = "b")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0538]: multiple 'since' items
   --> $DIR/deprecation-sanity.rs:30:27

src/test/ui/stability-attribute/stability-attribute-sanity.rs

@@ -59,14 +59,14 @@ fn multiple3() { }
 
 #[stable(feature = "a", since = "b")]
 #[rustc_deprecated(since = "b", reason = "text")]
-#[rustc_deprecated(since = "b", reason = "text")]
+#[rustc_deprecated(since = "b", reason = "text")] //~ ERROR multiple deprecated attributes
 #[rustc_const_unstable(feature = "c", issue = "none")]
 #[rustc_const_unstable(feature = "d", issue = "none")] //~ ERROR multiple stability levels
-pub const fn multiple4() { } //~ ERROR multiple deprecated attributes
+pub const fn multiple4() { }
 //~^ ERROR Invalid stability or deprecation version found
 
 #[rustc_deprecated(since = "a", reason = "text")]
 fn deprecated_without_unstable_or_stable() { }
-//~^ ERROR rustc_deprecated attribute must be paired with either stable or unstable attribute
+//~^^ ERROR rustc_deprecated attribute must be paired with either stable or unstable attribute
 
 fn main() { }

src/test/ui/stability-attribute/stability-attribute-sanity.stderr

@@ -83,10 +83,16 @@ LL | #[stable(feature = "a", since = "b")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0550]: multiple deprecated attributes
-  --> $DIR/stability-attribute-sanity.rs:65:1
+  --> $DIR/stability-attribute-sanity.rs:62:1
    |
-LL | pub const fn multiple4() { }
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[rustc_deprecated(since = "b", reason = "text")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: first deprecation attribute here
+  --> $DIR/stability-attribute-sanity.rs:61:1
+   |
+LL | #[rustc_deprecated(since = "b", reason = "text")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0544]: multiple stability levels
   --> $DIR/stability-attribute-sanity.rs:64:1
@@ -101,10 +107,10 @@ LL | pub const fn multiple4() { }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0549]: rustc_deprecated attribute must be paired with either stable or unstable attribute
-  --> $DIR/stability-attribute-sanity.rs:69:1
+  --> $DIR/stability-attribute-sanity.rs:68:1
    |
-LL | fn deprecated_without_unstable_or_stable() { }
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[rustc_deprecated(since = "a", reason = "text")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 18 previous errors