Rollup merge of #72306 - Aaron1011:feature/turbo-spacing, r=petrochenkov

Break tokens before checking if they are 'probably equal'

Fixes #68489
Fixes #70987

When checking two `TokenStreams` to see if they are 'probably equal',
we ignore the `IsJoint` information associated with each `TokenTree`.
However, the `IsJoint` information determines whether adjacent tokens
will be 'glued' (if possible) when construction the `TokenStream` - e.g.
`[Gt Gt]` can be 'glued' to `BinOp(Shr)`.

Since we are ignoring the `IsJoint` information, 'glued' and 'unglued'
tokens are equivalent for determining if two `TokenStreams` are
'probably equal'. Therefore, we need to 'unglue' all tokens in the
stream to avoid false negatives (which cause us to throw out the cached
tokens, losing span information).

src/test/ui/proc-macro/break-token-spans.rs

@@ -0,0 +1,16 @@
+// aux-build:test-macros.rs
+// Regression test for issues #68489 and #70987
+// Tests that we properly break tokens in `probably_equal_for_proc_macro`
+// See #72306
+//
+// Note that the weird spacing in this example is critical
+// for testing the issue.
+
+extern crate test_macros;
+
+#[test_macros::recollect_attr]
+fn repro() {
+    f :: < Vec < _ > > ( ) ; //~ ERROR cannot find
+    let a: Option<Option<u8>>= true; //~ ERROR mismatched
+}
+fn main() {}

src/test/ui/proc-macro/break-token-spans.stderr

@@ -0,0 +1,21 @@
+error[E0425]: cannot find function `f` in this scope
+  --> $DIR/break-token-spans.rs:13:5
+   |
+LL |     f :: < Vec < _ > > ( ) ;
+   |     ^ not found in this scope
+
+error[E0308]: mismatched types
+  --> $DIR/break-token-spans.rs:14:32
+   |
+LL |     let a: Option<Option<u8>>= true;
+   |            ------------------  ^^^^ expected enum `std::option::Option`, found `bool`
+   |            |
+   |            expected due to this
+   |
+   = note: expected enum `std::option::Option<std::option::Option<u8>>`
+              found type `bool`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0308, E0425.
+For more information about an error, try `rustc --explain E0308`.

src/test/ui/suggestions/issue-61963.rs

@@ -16,6 +16,7 @@ pub struct Qux<T>(T);
 
 #[dom_struct]
 pub struct Foo {
+    //~^ ERROR trait objects without an explicit `dyn` are deprecated [bare_trait_objects]
     qux: Qux<Qux<Baz>>,
     bar: Box<Bar>,
     //~^ ERROR trait objects without an explicit `dyn` are deprecated [bare_trait_objects]

src/test/ui/suggestions/issue-61963.stderr

@@ -1,5 +1,5 @@
 error: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/issue-61963.rs:20:14
+  --> $DIR/issue-61963.rs:21:14
    |
 LL |     bar: Box<Bar>,
    |              ^^^ help: use `dyn`: `dyn Bar`
@@ -10,5 +10,11 @@ note: the lint level is defined here
 LL | #![deny(bare_trait_objects)]
    |         ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/issue-61963.rs:18:1
+   |
+LL | pub struct Foo {
+   | ^^^ help: use `dyn`: `dyn pub`
+
+error: aborting due to 2 previous errors