rustc: make type_alias_missing_bounds warn-by-default.

Author: eddyb

src/librustc/lint/builtin.rs

@@ -340,7 +340,7 @@ declare_lint! {
 
 declare_lint! {
     pub TYPE_ALIAS_MISSING_BOUNDS,
-    Deny,
+    Warn,
     "type aliases missing bounds required by the type being aliased, are now deprecated"
 }
 

src/test/ui/type/issue-51626.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![deny(type_alias_missing_bounds)]
+
 pub trait Trait {}
 
 pub struct Foo<T: Trait>(T);

src/test/ui/type/issue-51626.stderr

@@ -1,16 +1,20 @@
 error: the trait bound `T: Trait` is not satisfied
-  --> $DIR/issue-51626.rs:17:25
+  --> $DIR/issue-51626.rs:19:25
    |
 LL | pub type Bar<T = Qux> = Foo<T>;
    |                         ^^^^^^ the trait `Trait` is not implemented for `T`
    |
-   = note: #[deny(type_alias_missing_bounds)] on by default
+note: lint level defined here
+  --> $DIR/issue-51626.rs:11:9
+   |
+LL | #![deny(type_alias_missing_bounds)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: consider adding a `where T: Trait` bound
    = help: missing bounds in type aliases were previously allowed
    = help: this is a hard error in Rust 2018
 
 error: the trait bound `Qux: Trait` is not satisfied
-  --> $DIR/issue-51626.rs:20:1
+  --> $DIR/issue-51626.rs:22:1
    |
 LL | pub type Baz<T: Trait = Qux> = Foo<T>;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `Qux`

src/test/ui/type/type-alias-bounds-err.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![allow(dead_code)]
+#![deny(type_alias_missing_bounds)]
 
 // This test contains examples originally in `type-alias-bounds.rs`,
 // that now produce errors instead of being silently accepted.

src/test/ui/type/type-alias-bounds-err.stderr

@@ -1,17 +1,21 @@
 error: `T` cannot be sent between threads safely
-  --> $DIR/type-alias-bounds-err.rs:18:22
+  --> $DIR/type-alias-bounds-err.rs:19:22
    |
 LL | type MySendable<T> = Sendable<T>;
    |                      ^^^^^^^^^^^ `T` cannot be sent between threads safely
    |
-   = note: #[deny(type_alias_missing_bounds)] on by default
+note: lint level defined here
+  --> $DIR/type-alias-bounds-err.rs:12:9
+   |
+LL | #![deny(type_alias_missing_bounds)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: the trait `std::marker::Send` is not implemented for `T`
    = help: consider adding a `where T: std::marker::Send` bound
    = help: missing bounds in type aliases were previously allowed
    = help: this is a hard error in Rust 2018
 
 error: the trait bound `U: Bound` is not satisfied
-  --> $DIR/type-alias-bounds-err.rs:22:14
+  --> $DIR/type-alias-bounds-err.rs:23:14
    |
 LL | type T4<U> = <U as Bound>::Assoc;
    |              ^^^^^^^^^^^^^^^^^^^ the trait `Bound` is not implemented for `U`