tests: issue-34798.rs => allow-phantomdata-in-ffi.rs

src/tools/tidy/src/issues.txt

@@ -2750,7 +2750,6 @@ ui/lint/issue-1866.rs
 ui/lint/issue-19102.rs
 ui/lint/issue-20343.rs
 ui/lint/issue-30302.rs
-ui/lint/issue-34798.rs
 ui/lint/issue-35075.rs
 ui/lint/issue-47775-nested-macro-unnecessary-parens-arg.rs
 ui/lint/issue-49588-non-shorthand-field-patterns-in-pattern-macro.rs

tests/ui/lint/improper_ctypes/allow-phantomdata-in-ffi.rs

@@ -1,6 +1,8 @@
 //@ run-pass
 #![forbid(improper_ctypes)]
 #![allow(dead_code)]
+// issue https://github.com/rust-lang/rust/issues/34798
+// We allow PhantomData in FFI so bindgen can bind templated C++ structs with "unused generic args"
 
 #[repr(C)]
 pub struct Foo {