9 files changed, 117 insertions, 6 deletions
diff --git a/tests/ui/inference/char-as-str-single.fixed b/tests/ui/inference/char-as-str-single.fixed
index bab1854dc..1621a279f 100644
--- a/tests/ui/inference/char-as-str-single.fixed
+++ b/tests/ui/inference/char-as-str-single.fixed
@@ -10,3 +10,12 @@ fn main() {
     let _: char = '人'; //~ ERROR mismatched types
     let _: char = '\''; //~ ERROR mismatched types
 }
+
+// regression test for https://github.com/rust-lang/rust/issues/109586
+#[allow(dead_code)]
+fn convert_c_to_str(c: char) {
+    match c {
+        'A' => {} //~ ERROR mismatched types
+        _ => {}
+    }
+}
diff --git a/tests/ui/inference/char-as-str-single.rs b/tests/ui/inference/char-as-str-single.rs
index 736920643..2903142f1 100644
--- a/tests/ui/inference/char-as-str-single.rs
+++ b/tests/ui/inference/char-as-str-single.rs
@@ -10,3 +10,12 @@ fn main() {
     let _: char = "人"; //~ ERROR mismatched types
     let _: char = "'"; //~ ERROR mismatched types
 }
+
+// regression test for https://github.com/rust-lang/rust/issues/109586
+#[allow(dead_code)]
+fn convert_c_to_str(c: char) {
+    match c {
+        "A" => {} //~ ERROR mismatched types
+        _ => {}
+    }
+}
diff --git a/tests/ui/inference/char-as-str-single.stderr b/tests/ui/inference/char-as-str-single.stderr
index 3375ec6ac..9149efe32 100644
--- a/tests/ui/inference/char-as-str-single.stderr
+++ b/tests/ui/inference/char-as-str-single.stderr
@@ -37,6 +37,19 @@ help: if you meant to write a `char` literal, use single quotes
 LL |     let _: char = '\'';
    |                   ~~~~
 
-error: aborting due to 3 previous errors
+error[E0308]: mismatched types
+  --> $DIR/char-as-str-single.rs:18:9
+   |
+LL |     match c {
+   |           - this expression has type `char`
+LL |         "A" => {}
+   |         ^^^ expected `char`, found `&str`
+   |
+help: if you meant to write a `char` literal, use single quotes
+   |
+LL |         'A' => {}
+   |         ~~~
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/inference/issue-80409.rs b/tests/ui/inference/issue-80409.rs
new file mode 100644
index 000000000..80cad6dfc
--- /dev/null
+++ b/tests/ui/inference/issue-80409.rs
@@ -0,0 +1,36 @@
+// check-pass
+
+#![allow(unreachable_code, unused)]
+
+use std::marker::PhantomData;
+
+struct FsmBuilder<TFsm> {
+    _fsm: PhantomData<TFsm>,
+}
+
+impl<TFsm> FsmBuilder<TFsm> {
+    fn state(&mut self) -> FsmStateBuilder<TFsm> {
+        todo!()
+    }
+}
+
+struct FsmStateBuilder<TFsm> {
+    _state: PhantomData<TFsm>,
+}
+
+impl<TFsm> FsmStateBuilder<TFsm> {
+    fn on_entry<TAction: Fn(&mut StateContext<'_, TFsm>)>(&self, _action: TAction) {}
+}
+
+trait Fsm {
+    type Context;
+}
+
+struct StateContext<'a, TFsm: Fsm> {
+    context: &'a mut TFsm::Context,
+}
+
+fn main() {
+    let mut builder: FsmBuilder<usize> = todo!();
+    builder.state().on_entry(|_| {});
+}
diff --git a/tests/ui/inference/issue-83606.stderr b/tests/ui/inference/issue-83606.stderr
index f2ee8692e..97ed53fb3 100644
--- a/tests/ui/inference/issue-83606.stderr
+++ b/tests/ui/inference/issue-83606.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed for `[usize; N]`
 LL |     let _ = foo("foo");
    |         ^
    |
-help: consider giving this pattern a type, where the the value of const parameter `N` is specified
+help: consider giving this pattern a type, where the value of const parameter `N` is specified
    |
 LL |     let _: [usize; N] = foo("foo");
    |          ++++++++++++
diff --git a/tests/ui/inference/need_type_info/concrete-impl.rs b/tests/ui/inference/need_type_info/concrete-impl.rs
index 72e0e74f3..fc79e6201 100644
--- a/tests/ui/inference/need_type_info/concrete-impl.rs
+++ b/tests/ui/inference/need_type_info/concrete-impl.rs
@@ -7,10 +7,13 @@ struct Two;
 struct Struct;
 
 impl Ambiguous<One> for Struct {}
+//~^ NOTE multiple `impl`s satisfying `Struct: Ambiguous<_>` found
 impl Ambiguous<Two> for Struct {}
 
 fn main() {
     <Struct as Ambiguous<_>>::method();
     //~^ ERROR type annotations needed
+    //~| NOTE cannot infer type of the type parameter `A`
     //~| ERROR type annotations needed
+    //~| NOTE infer type of the type parameter `A`
 }
diff --git a/tests/ui/inference/need_type_info/concrete-impl.stderr b/tests/ui/inference/need_type_info/concrete-impl.stderr
index aa3296995..74c3f6cd5 100644
--- a/tests/ui/inference/need_type_info/concrete-impl.stderr
+++ b/tests/ui/inference/need_type_info/concrete-impl.stderr
@@ -1,20 +1,21 @@
 error[E0282]: type annotations needed
-  --> $DIR/concrete-impl.rs:13:5
+  --> $DIR/concrete-impl.rs:14:5
    |
 LL |     <Struct as Ambiguous<_>>::method();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `Self` declared on the trait `Ambiguous`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `A` declared on the trait `Ambiguous`
 
 error[E0283]: type annotations needed
-  --> $DIR/concrete-impl.rs:13:5
+  --> $DIR/concrete-impl.rs:14:5
    |
 LL |     <Struct as Ambiguous<_>>::method();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `Self` declared on the trait `Ambiguous`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `A` declared on the trait `Ambiguous`
    |
 note: multiple `impl`s satisfying `Struct: Ambiguous<_>` found
   --> $DIR/concrete-impl.rs:9:1
    |
 LL | impl Ambiguous<One> for Struct {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
 LL | impl Ambiguous<Two> for Struct {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/tests/ui/inference/need_type_info/issue-109905.rs b/tests/ui/inference/need_type_info/issue-109905.rs
new file mode 100644
index 000000000..99d10a5ea
--- /dev/null
+++ b/tests/ui/inference/need_type_info/issue-109905.rs
@@ -0,0 +1,25 @@
+// Test that we show the correct type parameter that couldn't be inferred and that we don't
+// end up stating nonsense like "type parameter `'a`" which we used to do.
+
+trait Trait<'a, T> {
+    fn m(self);
+}
+
+impl<'a, A> Trait<'a, A> for () {
+    fn m(self) {}
+}
+
+fn qualified() {
+    <() as Trait<'static, _>>::m(());
+    //~^ ERROR type annotations needed
+    //~| NOTE cannot infer type of the type parameter `T`
+
+}
+
+fn unqualified() {
+    Trait::<'static, _>::m(());
+    //~^ ERROR type annotations needed
+    //~| NOTE cannot infer type of the type parameter `T`
+}
+
+fn main() {}
diff --git a/tests/ui/inference/need_type_info/issue-109905.stderr b/tests/ui/inference/need_type_info/issue-109905.stderr
new file mode 100644
index 000000000..fcdd50f14
--- /dev/null
+++ b/tests/ui/inference/need_type_info/issue-109905.stderr
@@ -0,0 +1,15 @@
+error[E0282]: type annotations needed
+  --> $DIR/issue-109905.rs:13:5
+   |
+LL |     <() as Trait<'static, _>>::m(());
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the trait `Trait`
+
+error[E0282]: type annotations needed
+  --> $DIR/issue-109905.rs:20:5
+   |
+LL |     Trait::<'static, _>::m(());
+   |     ^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the trait `Trait`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0282`.