Auto merge of #48849 - Manishearth:rollup, r=Manishearth

Rollup of 7 pull requests

- Successful merges: #48292, #48682, #48699, #48738, #48752, #48789, #48808
- Failed merges:

src/libcore/num/mod.rs

@@ -3900,6 +3900,13 @@ fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32) -> Result<T, Par
 /// This error is used as the error type for the `from_str_radix()` functions
 /// on the primitive integer types, such as [`i8::from_str_radix`].
 ///
+/// # Potential causes
+///
+/// Among other causes, `ParseIntError` can be thrown because of leading or trailing whitespace
+/// in the string e.g. when it is obtained from the standard input.
+/// Using the [`str.trim()`] method ensures that no whitespace remains before parsing.
+///
+/// [`str.trim()`]: ../../std/primitive.str.html#method.trim
 /// [`i8::from_str_radix`]: ../../std/primitive.i8.html#method.from_str_radix
 #[derive(Debug, Clone, PartialEq, Eq)]
 #[stable(feature = "rust1", since = "1.0.0")]

src/librustc/hir/check_attr.rs

@@ -47,7 +47,13 @@ struct CheckAttrVisitor<'a, 'tcx: 'a> {
 impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
     /// Check any attribute.
     fn check_attributes(&self, item: &hir::Item, target: Target) {
-        self.tcx.trans_fn_attrs(self.tcx.hir.local_def_id(item.id));
+        if target == Target::Fn {
+            self.tcx.trans_fn_attrs(self.tcx.hir.local_def_id(item.id));
+        } else if let Some(a) = item.attrs.iter().find(|a| a.check_name("target_feature")) {
+            self.tcx.sess.struct_span_err(a.span, "attribute should be applied to a function")
+                .span_label(item.span, "not a function")
+                .emit();
+        }
 
         for attr in &item.attrs {
             if let Some(name) = attr.name() {

src/librustc/infer/error_reporting/mod.rs

@@ -138,9 +138,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 self.explain_span(scope_decorated_tag, span)
             }
 
-            ty::ReEarlyBound(_) | ty::ReFree(_) => self.msg_span_from_free_region(region),
-
-            ty::ReStatic => ("the static lifetime".to_owned(), None),
+            ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic => {
+                self.msg_span_from_free_region(region)
+            }
 
             ty::ReEmpty => ("the empty lifetime".to_owned(), None),
 
@@ -175,6 +175,19 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     fn msg_span_from_free_region(self, region: ty::Region<'tcx>) -> (String, Option<Span>) {
+        match *region {
+            ty::ReEarlyBound(_) | ty::ReFree(_)  => {
+                self.msg_span_from_early_bound_and_free_regions(region)
+            },
+            ty::ReStatic => ("the static lifetime".to_owned(), None),
+            _ => bug!(),
+        }
+    }
+
+    fn msg_span_from_early_bound_and_free_regions(
+        self,
+        region: ty::Region<'tcx>,
+    ) -> (String, Option<Span>) {
         let scope = region.free_region_binding_scope(self);
         let node = self.hir.as_local_node_id(scope).unwrap_or(DUMMY_NODE_ID);
         let unknown;