Only apply ProceduralMasquerade hack to older versions of rental

The latest version of `rental` (v0.5.6) contains a fix that allows it to
compile without relying on the pretty-print back-compat hack.

Hopefully, there are no longer any crates relying on the affected
versions of the (much less popular) `procedural-masquerade` crate. This
should allow us to target the pretty-print back-compat hack specifically
to older versions of `rental`, and specifically mention upgrading to
`rental` v0.5.6 in the lint message.

src/test/ui/proc-macro/issue-73933-procedural-masquerade.rs

@@ -1,18 +1,11 @@
 // aux-build:test-macros.rs
+// check-pass
 
 #[macro_use]
 extern crate test_macros;
 
 #[derive(Print)]
 enum ProceduralMasqueradeDummyType {
-//~^ ERROR using
-//~| WARN this was previously
-//~| ERROR using
-//~| WARN this was previously
-//~| ERROR using
-//~| WARN this was previously
-//~| ERROR using
-//~| WARN this was previously
     Input
 }
 

src/test/ui/proc-macro/issue-73933-procedural-masquerade.stderr

@@ -1,91 +0,0 @@
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-   = note: `#[deny(proc_macro_back_compat)]` on by default
-
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-
-error: aborting due to 4 previous errors
-
-Future incompatibility report: Future breakage diagnostic:
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-   = note: `#[deny(proc_macro_back_compat)]` on by default
-
-Future breakage diagnostic:
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-   = note: `#[deny(proc_macro_back_compat)]` on by default
-
-Future breakage diagnostic:
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-   = note: `#[deny(proc_macro_back_compat)]` on by default
-
-Future breakage diagnostic:
-error: using `procedural-masquerade` crate
-  --> $DIR/issue-73933-procedural-masquerade.rs:7:6
-   |
-LL | enum ProceduralMasqueradeDummyType {
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
-   = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
-   = note: `#[deny(proc_macro_back_compat)]` on by default
-

src/test/ui/proc-macro/issue-73933-procedural-masquerade.stdout

@@ -1,22 +1,21 @@
-PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input, }
-PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input }
+PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input }
 PRINT-DERIVE INPUT (DEBUG): TokenStream [
     Ident {
         ident: "enum",
-        span: #0 bytes(86..90),
+        span: #0 bytes(100..104),
     },
     Ident {
         ident: "ProceduralMasqueradeDummyType",
-        span: #0 bytes(91..120),
+        span: #0 bytes(105..134),
     },
     Group {
         delimiter: Brace,
         stream: TokenStream [
             Ident {
                 ident: "Input",
-                span: #0 bytes(315..320),
+                span: #0 bytes(141..146),
             },
         ],
-        span: #0 bytes(121..322),
+        span: #0 bytes(135..148),
     },
 ]

src/test/ui/proc-macro/pretty-print-hack-hide.rs

@@ -0,0 +1,12 @@
+// aux-build:test-macros.rs
+// compile-flags: -Z span-debug
+// check-pass
+
+#![no_std] // Don't load unnecessary hygiene information from std
+extern crate std;
+
+#[macro_use] extern crate test_macros;
+
+include!("pretty-print-hack/rental-0.5.6/src/lib.rs");
+
+fn main() {}

src/test/ui/proc-macro/pretty-print-hack-hide.stdout

@@ -0,0 +1,21 @@
+PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input }
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
+    Ident {
+        ident: "enum",
+        span: $DIR/pretty-print-hack/rental-0.5.6/src/lib.rs:4:1: 4:5 (#0),
+    },
+    Ident {
+        ident: "ProceduralMasqueradeDummyType",
+        span: $DIR/pretty-print-hack/rental-0.5.6/src/lib.rs:4:6: 4:35 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [
+            Ident {
+                ident: "Input",
+                span: $DIR/pretty-print-hack/rental-0.5.6/src/lib.rs:13:5: 13:10 (#0),
+            },
+        ],
+        span: $DIR/pretty-print-hack/rental-0.5.6/src/lib.rs:4:36: 14:2 (#0),
+    },
+]

src/test/ui/proc-macro/pretty-print-hack-show.rs

@@ -0,0 +1,17 @@
+// aux-build:test-macros.rs
+// compile-flags: -Z span-debug
+
+#![no_std] // Don't load unnecessary hygiene information from std
+extern crate std;
+
+#[macro_use] extern crate test_macros;
+
+mod first {
+    include!("pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs");
+}
+
+mod second {
+    include!("pretty-print-hack/rental-0.5.5/src/lib.rs");
+}
+
+fn main() {}

src/test/ui/proc-macro/pretty-print-hack-show.stderr

@@ -0,0 +1,179 @@
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+
+error: aborting due to 8 previous errors
+
+Future incompatibility report: Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+
+Future breakage diagnostic:
+error: using an old version of `rental`
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+   |
+LL | enum ProceduralMasqueradeDummyType {
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = 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 #83125 <https://github.com/rust-lang/rust/issues/83125>
+   = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
+   = note: `#[deny(proc_macro_back_compat)]` on by default
+

src/test/ui/proc-macro/pretty-print-hack-show.stdout

@@ -0,0 +1,44 @@
+PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input, }
+PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input }
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
+    Ident {
+        ident: "enum",
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:1: 4:5 (#0),
+    },
+    Ident {
+        ident: "ProceduralMasqueradeDummyType",
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6: 4:35 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [
+            Ident {
+                ident: "Input",
+                span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:13:5: 13:10 (#0),
+            },
+        ],
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:36: 14:2 (#0),
+    },
+]
+PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input, }
+PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input }
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
+    Ident {
+        ident: "enum",
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:1: 4:5 (#0),
+    },
+    Ident {
+        ident: "ProceduralMasqueradeDummyType",
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6: 4:35 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [
+            Ident {
+                ident: "Input",
+                span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:13:5: 13:10 (#0),
+            },
+        ],
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:36: 14:2 (#0),
+    },
+]

src/test/ui/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs

@@ -0,0 +1,14 @@
+// ignore-test
+
+#[derive(Print)]
+enum ProceduralMasqueradeDummyType {
+//~^ ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+    Input
+}

src/test/ui/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs

@@ -0,0 +1,14 @@
+// ignore-test
+
+#[derive(Print)]
+enum ProceduralMasqueradeDummyType {
+//~^ ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+    Input
+}

src/test/ui/proc-macro/pretty-print-hack/rental-0.5.6/src/lib.rs

@@ -0,0 +1,14 @@
+// ignore-test
+
+#[derive(Print)]
+enum ProceduralMasqueradeDummyType {
+//~^ ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+//~| ERROR using
+//~| WARN this was previously
+    Input
+}