Avoid extra path trimming in method not found error

Method errors have an extra check that force trim paths whenever the
normal string is longer than 10 characters, which can be quite unhelpful
when multiple items have the same name (for example an `Error`).

A user reported this force trimming as being quite unhelpful when they
had a method error where the precise path of the `Error` mattered.

The code uses `tcx.short_string` already to get the normal path, which
tries to be clever around trimming paths if necessary, so there is no
reason for this extra force trimming.

5 files changed, 23 insertions, 3 deletions

diff --git a/tests/ui/methods/issue-19521.stderr b/tests/ui/methods/issue-19521.stderr
index f451dc36d45..2ef83a4792a 100644
--- a/tests/ui/methods/issue-19521.stderr
+++ b/tests/ui/methods/issue-19521.stderr
@@ -2,7 +2,7 @@ error[E0599]: no method named `homura` found for reference `&'static str` in the
   --> $DIR/issue-19521.rs:2:8
    |
 LL |     "".homura()();
-   |        ^^^^^^ method not found in `&str`
+   |        ^^^^^^ method not found in `&'static str`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/methods/method-not-found-generic-arg-elision.stderr b/tests/ui/methods/method-not-found-generic-arg-elision.stderr
index a665500fd9e..8429c3aebac 100644
--- a/tests/ui/methods/method-not-found-generic-arg-elision.stderr
+++ b/tests/ui/methods/method-not-found-generic-arg-elision.stderr
@@ -23,7 +23,7 @@ error[E0599]: no method named `extend` found for struct `Map` in the current sco
   --> $DIR/method-not-found-generic-arg-elision.rs:87:67
    |
 LL |     v.iter().map(Box::new(|x| x * x) as Box<dyn Fn(&i32) -> i32>).extend(std::iter::once(100));
-   |                                                                   ^^^^^^ method not found in `Map<Iter<'_, i32>, Box<dyn Fn(&i32) -> i32>>`
+   |                                                                   ^^^^^^ method not found in `Map<std::slice::Iter<'_, i32>, Box<dyn for<'a> Fn(&'a i32) -> i32>>`
 
 error[E0599]: no method named `method` found for struct `Wrapper<bool>` in the current scope
   --> $DIR/method-not-found-generic-arg-elision.rs:90:13
diff --git a/tests/ui/methods/receiver-equality.stderr b/tests/ui/methods/receiver-equality.stderr
index cea3340e386..bf149cc2eb4 100644
--- a/tests/ui/methods/receiver-equality.stderr
+++ b/tests/ui/methods/receiver-equality.stderr
@@ -5,7 +5,7 @@ LL | struct B<T>(T);
    | ----------- function or associated item `method` not found for this struct
 ...
 LL |     B::<for<'a> fn(&'a ())>::method(y);
-   |                              ^^^^^^ function or associated item not found in `B<fn(&())>`
+   |                              ^^^^^^ function or associated item not found in `B<for<'a> fn(&'a ())>`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/methods/untrimmed-path-type.rs b/tests/ui/methods/untrimmed-path-type.rs
new file mode 100644
index 00000000000..e6e3ad79185
--- /dev/null
+++ b/tests/ui/methods/untrimmed-path-type.rs
@@ -0,0 +1,11 @@
+// Ensures that the path of the `Error` type is not trimmed
+// to make it clear which Error type is meant.
+
+fn main() {
+   meow().unknown(); //~ ERROR no method named `unknown` found
+   //~^ NOTE method not found in `Result<(), std::io::Error>`
+}
+
+fn meow() -> Result<(), std::io::Error> {
+    Ok(())
+}
diff --git a/tests/ui/methods/untrimmed-path-type.stderr b/tests/ui/methods/untrimmed-path-type.stderr
new file mode 100644
index 00000000000..1f3101ff4e7
--- /dev/null
+++ b/tests/ui/methods/untrimmed-path-type.stderr
@@ -0,0 +1,9 @@
+error[E0599]: no method named `unknown` found for enum `Result` in the current scope
+  --> $DIR/untrimmed-path-type.rs:5:11
+   |
+LL |    meow().unknown();
+   |           ^^^^^^^ method not found in `Result<(), std::io::Error>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.