make lint warn by default

src/librustc_session/lint/builtin.rs

@@ -262,7 +262,7 @@ declare_lint! {
 
 declare_lint! {
     pub COHERENCE_LEAK_CHECK,
-    Deny,
+    Warn,
     "distinct impls distinguished only by the leak-check code",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #56105 <https://github.com/rust-lang/rust/issues/56105>",

src/test/ui/coherence/coherence-subtyping.old.stderr

@@ -1,16 +1,14 @@
-error: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
-  --> $DIR/coherence-subtyping.rs:15:1
+warning: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
+  --> $DIR/coherence-subtyping.rs:16:1
    |
 LL | impl TheTrait for for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {}
    | ---------------------------------------------------------- first implementation here
 LL | 
 LL | impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
    |
-   = note: `#[deny(coherence_leak_check)]` on by default
+   = note: `#[warn(coherence_leak_check)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
    = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
-error: aborting due to previous error
-

src/test/ui/coherence/coherence-subtyping.re.stderr

@@ -1,16 +1,14 @@
-error: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
-  --> $DIR/coherence-subtyping.rs:15:1
+warning: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
+  --> $DIR/coherence-subtyping.rs:16:1
    |
 LL | impl TheTrait for for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {}
    | ---------------------------------------------------------- first implementation here
 LL | 
 LL | impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
    |
-   = note: `#[deny(coherence_leak_check)]` on by default
+   = note: `#[warn(coherence_leak_check)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
    = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
-error: aborting due to previous error
-

src/test/ui/coherence/coherence-subtyping.rs

@@ -5,6 +5,7 @@
 // universe transition (#56105) may eventually become an error.
 
 // revisions: old re
+// check-pass
 
 trait TheTrait {
     fn foo(&self) {}
@@ -13,9 +14,9 @@ trait TheTrait {
 impl TheTrait for for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {}
 
 impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
-    //[re]~^ ERROR conflicting implementation
+    //[re]~^ WARNING conflicting implementation
     //[re]~^^ WARNING this was previously accepted by the compiler but is being phased out
-    //[old]~^^^ ERROR conflicting implementation
+    //[old]~^^^ WARNING conflicting implementation
     //[old]~^^^^ WARNING this was previously accepted by the compiler but is being phased out
 }