Update Error format for E0516, E0517, E0518

src/librustc/hir/check_attr.rs

@@ -42,7 +42,9 @@ struct CheckAttrVisitor<'a> {
 impl<'a> CheckAttrVisitor<'a> {
  fn check_inline(&self, attr: &ast::Attribute, target: Target) {
  if target != Target::Fn {
- span_err!(self.sess, attr.span, E0518, "attribute should be applied to function");
+ struct_span_err!(self.sess, attr.span, E0518, "attribute should be applied to function")
+ .span_label(attr.span, &format!("requires a function"))
+ .emit();
  }
  }
 
@@ -56,18 +58,20 @@ impl<'a> CheckAttrVisitor<'a> {
 
  let mut conflicting_reprs = 0;
  for word in words {
+
  let name = match word.name() {
  Some(word) => word,
  None => continue,
  };
 
- let message = match &*name {
+ let (message, label) = match &*name {
  "C" => {
  conflicting_reprs += 1;
  if target != Target::Struct &&
  target != Target::Union &&
  target != Target::Enum {
- "attribute should be applied to struct, enum or union"
+ ("attribute should be applied to struct, enum or union",
+ "a struct, enum or union")
  } else {
  continue
  }
@@ -77,15 +81,17 @@ impl<'a> CheckAttrVisitor<'a> {
  // can be used to modify another repr hint
  if target != Target::Struct &&
  target != Target::Union {
- "attribute should be applied to struct or union"
+ ("attribute should be applied to struct or union",
+ "a struct or union")
  } else {
  continue
  }
  }
  "simd" => {
  conflicting_reprs += 1;
  if target != Target::Struct {
- "attribute should be applied to struct"
+ ("attribute should be applied to struct",
+ "a struct")
  } else {
  continue
  }
@@ -95,15 +101,17 @@ impl<'a> CheckAttrVisitor<'a> {
  "isize" | "usize" => {
  conflicting_reprs += 1;
  if target != Target::Enum {
- "attribute should be applied to enum"
+ ("attribute should be applied to enum",
+ "an enum")
  } else {
  continue
  }
  }
  _ => continue,
  };
-
- span_err!(self.sess, attr.span, E0517, "{}", message);
+ struct_span_err!(self.sess, attr.span, E0517, "{}", message)
+ .span_label(attr.span, &format!("requires {}", label))
+ .emit();
  }
  if conflicting_reprs > 1 {
  span_warn!(self.sess, attr.span, E0566,

src/librustc_typeck/astconv.rs

@@ -1769,8 +1769,11 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
  }
  }
  hir::TyTypeof(ref _e) => {
- span_err!(tcx.sess, ast_ty.span, E0516,
- "`typeof` is a reserved keyword but unimplemented");
+ struct_span_err!(tcx.sess, ast_ty.span, E0516,
+ "`typeof` is a reserved keyword but unimplemented")
+ .span_label(ast_ty.span, &format!("reserved keyword"))
+ .emit();
+
  tcx.types.err
  }
  hir::TyInfer => {

src/test/compile-fail/E0516.rs

@@ -10,4 +10,5 @@
 
 fn main() {
  let x: typeof(92) = 92; //~ ERROR E0516
+ //~| reserved keyword
 }

src/test/compile-fail/E0517.rs

@@ -9,15 +9,19 @@
 // except according to those terms.
 
 #[repr(C)] //~ ERROR E0517
+ //~| requires a struct, enum or union
 type Foo = u8;
 
 #[repr(packed)] //~ ERROR E0517
+ //~| requires a struct
 enum Foo2 {Bar, Baz}
 
 #[repr(u8)] //~ ERROR E0517
+ //~| requires an enum
 struct Foo3 {bar: bool, baz: bool}
 
 #[repr(C)] //~ ERROR E0517
+ //~| requires a struct, enum or union
 impl Foo3 {
 }
 

src/test/compile-fail/E0518.rs

@@ -9,9 +9,11 @@
 // except according to those terms.
 
 #[inline(always)] //~ ERROR E0518
+ //~| requires a function
 struct Foo;
 
 #[inline(never)] //~ ERROR E0518
+ //~| requires a function
 impl Foo {
 }