Don't inline tainted MIR bodies

compiler/rustc_mir_transform/src/inline.rs

@@ -209,6 +209,9 @@ impl<'tcx> Inliner<'tcx> {
 
  let callee_body = try_instance_mir(self.tcx, callsite.callee.def)?;
  self.check_mir_body(callsite, callee_body, callee_attrs, cross_crate_inlinable)?;
+ if let Some(_) = callee_body.tainted_by_errors {
+ return Err("Body is tainted");
+ }
 
  if !self.tcx.consider_optimizing(|| {
  format!("Inline {:?} into {:?}", callsite.callee, caller_body.source)

tests/crashes/122909.rs → tests/ui/polymorphization/inline-tainted-body.rs

@@ -1,15 +1,21 @@
 //@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes
-//@ known-bug: #122909
 
+#![feature(unboxed_closures)]
 
-use std::sync::{Arc, Context, Weak};
+use std::sync::Arc;
 
 pub struct WeakOnce<T>();
+//~^ ERROR type parameter `T` is never used
+
 impl<T> WeakOnce<T> {
  extern "rust-call" fn try_get(&self) -> Option<Arc<T>> {}
+ //~^ ERROR functions with the "rust-call" ABI must take a single non-self tuple argument
+ //~| ERROR mismatched types
 
  pub fn get(&self) -> Arc<T> {
  self.try_get()
  .unwrap_or_else(|| panic!("Singleton {} not available", std::any::type_name::<T>()))
  }
 }
+
+fn main() {}

tests/ui/polymorphization/inline-tainted-body.stderr

@@ -0,0 +1,30 @@
+error[E0392]: type parameter `T` is never used
+ --> $DIR/inline-tainted-body.rs:7:21
+ |
+LL | pub struct WeakOnce<T>();
+ | ^ unused type parameter
+ |
+ = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
+ = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
+
+error: functions with the "rust-call" ABI must take a single non-self tuple argument
+ --> $DIR/inline-tainted-body.rs:11:35
+ |
+LL | extern "rust-call" fn try_get(&self) -> Option<Arc<T>> {}
+ | ^^^^^
+
+error[E0308]: mismatched types
+ --> $DIR/inline-tainted-body.rs:11:45
+ |
+LL | extern "rust-call" fn try_get(&self) -> Option<Arc<T>> {}
+ | ------- ^^^^^^^^^^^^^^ expected `Option<Arc<T>>`, found `()`
+ | |
+ | implicitly returns `()` as its body has no tail or `return` expression
+ |
+ = note: expected enum `Option<Arc<T>>`
+ found unit type `()`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0308, E0392.
+For more information about an error, try `rustc --explain E0308`.