Skip lifetimes in turbofish suggestions

Author: estebank

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1571,6 +1571,11 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
                                     generics
                                         .params
                                         .iter()
+                                        // Do not suggest `foo::<'a, T>()`
+                                        .filter(|p| !matches!(
+                                            p.kind,
+                                            ty::GenericParamDefKind::Lifetime
+                                        ))
                                         .map(|p| p.name.to_string())
                                         .collect::<Vec<String>>()
                                         .join(", ")

src/test/ui/issues/issue-12187-2.stderr

@@ -10,8 +10,8 @@ LL |     let &v: &T = new();
    |           ^^^^
 help: consider specifying the type arguments in the function call
    |
-LL |     let &v = new::<'r, T>();
-   |                 ^^^^^^^^^
+LL |     let &v = new::<T>();
+   |                 ^^^^^
 
 error: aborting due to previous error