Rollup merge of #98610 - lcnr:emit_inference_failure_err-ice, r=estebank

fix `emit_inference_failure_err` ICE

fixes #98598

this fix doesn't make me too happy, but :shrug:

6 files changed, 100 insertions, 0 deletions

diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.rs b/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.rs
new file mode 100644
index 00000000000..42af9fa8d11
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.rs
@@ -0,0 +1,21 @@
+trait Foo {
+    type Output;
+
+    fn baz() -> Self::Output;
+}
+
+fn needs_infer<T>() {}
+
+enum Bar {
+    Variant {}
+}
+
+impl Foo for u8 {
+    type Output = Bar;
+    fn baz() -> Self::Output {
+        needs_infer(); //~ ERROR type annotations needed
+        Self::Output::Variant {}
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.stderr b/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.stderr
new file mode 100644
index 00000000000..68ecb381348
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-enum.stderr
@@ -0,0 +1,14 @@
+error[E0282]: type annotations needed
+  --> $DIR/expr-struct-type-relative-enum.rs:16:9
+   |
+LL |         needs_infer();
+   |         ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `needs_infer`
+   |
+help: consider specifying the generic argument
+   |
+LL |         needs_infer::<T>();
+   |                    +++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs
new file mode 100644
index 00000000000..bcd29bb4e34
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs
@@ -0,0 +1,21 @@
+#![feature(generic_associated_types)]
+
+trait Foo {
+    type Output<T>;
+
+    fn baz();
+}
+
+enum Bar<T> {
+    Simple {},
+    Generic(T),
+}
+
+impl Foo for u8 {
+    type Output<T> = Bar<T>;
+    fn baz() {
+        Self::Output::Simple {}; //~ ERROR type annotations needed
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr
new file mode 100644
index 00000000000..65a75b68c1f
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr
@@ -0,0 +1,9 @@
+error[E0282]: type annotations needed
+  --> $DIR/expr-struct-type-relative-gat.rs:17:9
+   |
+LL |         Self::Output::Simple {};
+   |         ^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the associated type `Output`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative.rs b/src/test/ui/inference/need_type_info/expr-struct-type-relative.rs
new file mode 100644
index 00000000000..c3ece2b16cf
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative.rs
@@ -0,0 +1,21 @@
+// regression test for #98598
+
+trait Foo {
+    type Output;
+
+    fn baz() -> Self::Output;
+}
+
+fn needs_infer<T>() {}
+
+struct Bar {}
+
+impl Foo for u8 {
+    type Output = Bar;
+    fn baz() -> Self::Output {
+        needs_infer(); //~ ERROR type annotations needed
+        Self::Output {}
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative.stderr b/src/test/ui/inference/need_type_info/expr-struct-type-relative.stderr
new file mode 100644
index 00000000000..397d8e7be04
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative.stderr
@@ -0,0 +1,14 @@
+error[E0282]: type annotations needed
+  --> $DIR/expr-struct-type-relative.rs:16:9
+   |
+LL |         needs_infer();
+   |         ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `needs_infer`
+   |
+help: consider specifying the generic argument
+   |
+LL |         needs_infer::<T>();
+   |                    +++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.