Auto merge of #49799 - hdhoang:46205_deny_incoherent_fundamental_impls, r=nikomatsakis

lint: convert incoherent_fundamental_impls into hard error

*Summary for affected authors:* If your crate depends on one of the following crates, please upgrade to a newer version:
- gtk-rs: upgrade to at least 0.4
- rusqlite: upgrade to at least 0.14
- nalgebra: upgrade to at least 0.15, or the last patch version of 0.14
- spade: upgrade or refresh the Cargo.lock file to use version 1.7
- imageproc: upgrade to at least 0.16 (newer versions no longer use nalgebra)

implement #46205

r? @nikomatsakis

2 files changed, 2 insertions, 43 deletions

diff --git a/src/doc/rustc/src/lints/groups.md b/src/doc/rustc/src/lints/groups.md
index 46b717f3387..049e59b6517 100644
--- a/src/doc/rustc/src/lints/groups.md
+++ b/src/doc/rustc/src/lints/groups.md
@@ -21,9 +21,9 @@ Here's a list of each lint group, and the lints that they are made up of:
 | edition-2018        | Lints that will be turned into errors in Rust 2018            | tyvar-behind-raw-pointer                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
 | rust-2018-idioms    | Lints to nudge you toward idiomatic features of Rust 2018     | bare-trait-object, unreachable-pub                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 | unused              | These lints detect things being declared but not used         | unused-imports, unused-variables, unused-assignments, dead-code, unused-mut, unreachable-code, unreachable-patterns, unused-must-use, unused-unsafe, path-statements, unused-attributes, unused-macros, unused-allocation, unused-doc-comment, unused-extern-crates, unused-features, unused-parens                                                                                                                                                                                    |
-| future-incompatible | Lints that detect code that has future-compatibility problems | private-in-public, pub-use-of-private-extern-crate, patterns-in-fns-without-body, safe-extern-statics, invalid-type-param-default, legacy-directory-ownership, legacy-imports, legacy-constructor-visibility, missing-fragment-specifier, illegal-floating-point-literal-pattern, anonymous-parameters, parenthesized-params-in-types-and-modules, late-bound-lifetime-arguments, safe-packed-borrows, incoherent-fundamental-impls, tyvar-behind-raw-pointer, unstable-name-collision |
+| future-incompatible | Lints that detect code that has future-compatibility problems | private-in-public, pub-use-of-private-extern-crate, patterns-in-fns-without-body, safe-extern-statics, invalid-type-param-default, legacy-directory-ownership, legacy-imports, legacy-constructor-visibility, missing-fragment-specifier, illegal-floating-point-literal-pattern, anonymous-parameters, parenthesized-params-in-types-and-modules, late-bound-lifetime-arguments, safe-packed-borrows, tyvar-behind-raw-pointer, unstable-name-collision |
 
 Additionally, there's a `bad-style` lint group that's a deprecated alias for `nonstandard-style`.
 
 Finally, you can also see the table above by invoking `rustc -W help`. This will give you the exact values for the specific
-compiler you have installed.
\ No newline at end of file
+compiler you have installed.
diff --git a/src/doc/rustc/src/lints/listing/deny-by-default.md b/src/doc/rustc/src/lints/listing/deny-by-default.md
index fa62d1a03f5..c1740f272ed 100644
--- a/src/doc/rustc/src/lints/listing/deny-by-default.md
+++ b/src/doc/rustc/src/lints/listing/deny-by-default.md
@@ -222,44 +222,3 @@ error: invalid `crate_type` value
   | ^^^^^^^^^^^^^^^^^^^^
   |
 ```
-
-## incoherent-fundamental-impls
-
-This lint detects potentially-conflicting impls that were erroneously allowed. Some
-example code that triggers this lint:
-
-```rust,ignore
-pub trait Trait1<X> {
-    type Output;
-}
-
-pub trait Trait2<X> {}
-
-pub struct A;
-
-impl<X, T> Trait1<X> for T where T: Trait2<X> {
-    type Output = ();
-}
-
-impl<X> Trait1<Box<X>> for A {
-    type Output = i32;
-}
-```
-
-This will produce:
-
-```text
-error: conflicting implementations of trait `Trait1<std::boxed::Box<_>>` for type `A`: (E0119)
-  --> src/main.rs:13:1
-   |
-9  | impl<X, T> Trait1<X> for T where T: Trait2<X> {
-   | --------------------------------------------- first implementation here
-...
-13 | impl<X> Trait1<Box<X>> for A {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `A`
-   |
-   = note: #[deny(incoherent_fundamental_impls)] 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 #46205 <https://github.com/rust-lang/rust/issues/46205>
-   = note: downstream crates may implement trait `Trait2<std::boxed::Box<_>>` for type `A`
-```