Rollup merge of #89148 - estebank:used-type-param, r=oli-obk

Suggest `_` in turbofish if param will be inferred from fn argument

src/test/ui/suggestions/missing-type-param-used-in-param.fixed

@@ -0,0 +1,8 @@
+// run-rustfix
+
+fn two_type_params<A, B>(_: B) {}
+
+fn main() {
+    two_type_params::<String, _>(100); //~ ERROR this function takes 2 generic arguments
+    two_type_params::<String, _>(100);
+}

src/test/ui/suggestions/missing-type-param-used-in-param.rs

@@ -0,0 +1,8 @@
+// run-rustfix
+
+fn two_type_params<A, B>(_: B) {}
+
+fn main() {
+    two_type_params::<String>(100); //~ ERROR this function takes 2 generic arguments
+    two_type_params::<String, _>(100);
+}

src/test/ui/suggestions/missing-type-param-used-in-param.stderr

@@ -0,0 +1,21 @@
+error[E0107]: this function takes 2 generic arguments but 1 generic argument was supplied
+  --> $DIR/missing-type-param-used-in-param.rs:6:5
+   |
+LL |     two_type_params::<String>(100);
+   |     ^^^^^^^^^^^^^^^   ------ supplied 1 generic argument
+   |     |
+   |     expected 2 generic arguments
+   |
+note: function defined here, with 2 generic parameters: `A`, `B`
+  --> $DIR/missing-type-param-used-in-param.rs:3:4
+   |
+LL | fn two_type_params<A, B>(_: B) {}
+   |    ^^^^^^^^^^^^^^^ -  -
+help: add missing generic argument
+   |
+LL |     two_type_params::<String, _>(100);
+   |                             +++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0107`.