rollup merge of #17927 : alexcrichton/more-const

src/test/compile-fail/issue-17718-const-naming.rs

@@ -12,5 +12,6 @@
 
 const foo: int = 3;
 //~^ ERROR: should have an uppercase name such as
+//~^^ ERROR: constant item is never used
 
 fn main() {}

src/test/compile-fail/lint-dead-code-1.rs

@@ -35,6 +35,13 @@ pub static used_static2: int = used_static;
 const USED_STATIC: int = 0;
 const STATIC_USED_IN_ENUM_DISCRIMINANT: int = 10;
 
+pub const pub_const: int = 0;
+const priv_const: int = 0; //~ ERROR: constant item is never used
+const used_const: int = 0;
+pub const used_const2: int = used_const;
+const USED_CONST: int = 1;
+const CONST_USED_IN_ENUM_DISCRIMINANT: int = 11;
+
 pub type typ = *const UsedStruct4;
 pub struct PubStruct;
 struct PrivStruct; //~ ERROR: struct is never used
@@ -61,7 +68,10 @@ pub struct PubStruct2 {
 
 pub enum pub_enum { foo1, bar1 }
 pub enum pub_enum2 { a(*const StructUsedInEnum) }
-pub enum pub_enum3 { Foo = STATIC_USED_IN_ENUM_DISCRIMINANT }
+pub enum pub_enum3 {
+    Foo = STATIC_USED_IN_ENUM_DISCRIMINANT,
+    Bar = CONST_USED_IN_ENUM_DISCRIMINANT,
+}
 
 enum priv_enum { foo2, bar2 } //~ ERROR: enum is never used
 enum used_enum {
@@ -82,6 +92,7 @@ pub fn pub_fn() {
     let i = 1i;
     match i {
         USED_STATIC => (),
+        USED_CONST => (),
         _ => ()
     }
     f::<StructUsedInGeneric>();