Add a mir-opt test for dropping parameters

Author: scottmcm

tests/mir-opt/inline/inline_drop.drop_both_arguments.Inline.diff

@@ -0,0 +1,30 @@
+- // MIR for `drop_both_arguments` before Inline
++ // MIR for `drop_both_arguments` after Inline
+  
+  fn drop_both_arguments(_1: CallThingOnDrop, _2: CallThingOnDrop) -> () {
+      debug _a => _1;
+      debug _b => _2;
+      let mut _0: ();
+  
+      bb0: {
+          _0 = const ();
+          drop(_2) -> [return: bb1, unwind: bb3];
+      }
+  
+      bb1: {
+          drop(_1) -> [return: bb2, unwind: bb4];
+      }
+  
+      bb2: {
+          return;
+      }
+  
+      bb3 (cleanup): {
+          drop(_1) -> [return: bb4, unwind terminate(cleanup)];
+      }
+  
+      bb4 (cleanup): {
+          resume;
+      }
+  }
+  

tests/mir-opt/inline/inline_drop.rs

@@ -0,0 +1,24 @@
+// Test for inlining with an indirect destination place.
+//
+//@ test-mir-pass: Inline
+//@ edition: 2021
+//@ needs-unwind
+#![crate_type = "lib"]
+
+#[inline(never)]
+fn thing() {}
+
+struct CallThingOnDrop;
+
+impl Drop for CallThingOnDrop {
+    #[inline]
+    fn drop(&mut self) {
+        thing();
+    }
+}
+
+// EMIT_MIR inline_drop.drop_both_arguments.Inline.diff
+pub fn drop_both_arguments(_a: CallThingOnDrop, _b: CallThingOnDrop) {
+    // CHECK: drop(_2)
+    // CHECK: drop(_1)
+}