Add extra test for expressions and fix typo in message

Author: tejom

src/librustc/hir/check_attr.rs

@@ -250,7 +250,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
                     self.emit_repr_error(
                         attr.span,
                         stmt.span,
-                        &format!("attribute should not be applied a statement"),
+                        &format!("attribute should not be applied to a statement"),
                         &format!("not a struct, enum or union"),
                     );
                 }

src/test/compile-fail/issue-43988.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(stmt_expr_attributes)]
+
 fn main() {
 
     #[inline]
@@ -21,7 +23,7 @@ fn main() {
 
     #[repr(nothing)]
     let _x = 0;
-    //~^^ ERROR attribute should not be applied a statement
+    //~^^ ERROR attribute should not be applied to a statement
 
     #[repr(something_not_real)]
     loop {
@@ -31,12 +33,16 @@ fn main() {
 
     #[repr]
     let _y = "123";
-    //~^^ ERROR attribute should not be applied a statement
+    //~^^ ERROR attribute should not be applied to a statement
 
 
     fn foo() {}
 
     #[inline(ABC)]
     foo();
     //~^^ ERROR attribute should be applied to function
+
+    let _z = #[repr] 1;
+    //~^ ERROR attribute should not be applied to an expression
+
 }