Int and float inference variables are trivially copy

compiler/rustc_hir_analysis/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs

@@ -198,6 +198,10 @@ impl<'tcx> expr_use_visitor::Delegate<'tcx> for ExprUseDelegate<'tcx> {
 
         // If the type being assigned needs dropped, then the mutation counts as a borrow
         // since it is essentially doing `Drop::drop(&mut x); x = new_value;`.
+        //
+        // FIXME(drop-tracking): We need to be more responsible about inference
+        // variables here, since `needs_drop` is a "raw" type query, i.e. it
+        // basically requires types to have been fully resolved.
         if assignee_place.place.base_ty.needs_drop(self.tcx, self.param_env) {
             self.places
                 .borrowed

compiler/rustc_middle/src/ty/sty.rs

@@ -2205,7 +2205,10 @@ impl<'tcx> Ty<'tcx> {
             // These aren't even `Clone`
             ty::Str | ty::Slice(..) | ty::Foreign(..) | ty::Dynamic(..) => false,
 
-            ty::Int(..) | ty::Uint(..) | ty::Float(..) => true,
+            ty::Infer(ty::InferTy::FloatVar(_) | ty::InferTy::IntVar(_))
+            | ty::Int(..)
+            | ty::Uint(..)
+            | ty::Float(..) => true,
 
             // The voldemort ZSTs are fine.
             ty::FnDef(..) => true,

src/test/ui/generator/issue-102645.rs

@@ -0,0 +1,23 @@
+// compile-flags: -Zdrop-tracking
+
+#![feature(generators, generator_trait)]
+
+use std::ops::Generator;
+use std::pin::Pin;
+
+fn main() {
+    let mut a = 5;
+    let mut b = || {
+        let d = 6;
+        yield;
+        _zzz(); // #break
+        a = d;
+    };
+    Pin::new(&mut b).resume();
+    //~^ ERROR this function takes 1 argument but 0 arguments were supplied
+    // This type error is required to reproduce the ICE...
+}
+
+fn _zzz() {
+    ()
+}

src/test/ui/generator/issue-102645.stderr

@@ -0,0 +1,19 @@
+error[E0061]: this function takes 1 argument but 0 arguments were supplied
+  --> $DIR/issue-102645.rs:16:22
+   |
+LL |     Pin::new(&mut b).resume();
+   |                      ^^^^^^-- an argument of type `()` is missing
+   |
+note: associated function defined here
+  --> $SRC_DIR/core/src/ops/generator.rs:LL:COL
+   |
+LL |     fn resume(self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return>;
+   |        ^^^^^^
+help: provide the argument
+   |
+LL |     Pin::new(&mut b).resume(());
+   |                            ~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0061`.