Rollup merge of rust-lang#155218 - jakubadamw:issue-139570, r=tiif

coroutines: Skip the closure signature annotation check for tainted bodies

When a coroutine has too many parameters, `check_match` fails and `construct_error` builds a MIR body with only the coroutine's computed arguments (env + resume type). The user-provided signature, however, still reflects all the parameters the user wrote. `check_signature_annotation` then tries to `zip_eq` these two mismatched iterators, causing a panic. Checking `tainted_by_errors` and bailing early avoids this, since `construct_error` bodies cannot meaningfully be compared against user annotations.

Example currently ICEing:

```rust
fn main() {
    |(1, 42), ()| yield;
}
```

Closes rust-lang#139570.

Author: JonathanBrouwer

compiler/rustc_borrowck/src/type_check/input_output.rs

@@ -32,6 +32,15 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             return;
         }
 
+        // If the MIR body was constructed via `construct_error` (because an
+        // earlier pass like match checking failed), its args may not match
+        // the user-provided signature (e.g. a coroutine with too many
+        // parameters). Bail out as this can cause panic,
+        // see <https://github.com/rust-lang/rust/issues/139570>.
+        if self.body.tainted_by_errors.is_some() {
+            return;
+        }
+
         let user_provided_poly_sig = self.tcx().closure_user_provided_sig(mir_def_id);
 
         // Instantiate the canonicalized variables from user-provided signature

tests/crashes/139570.rs

@@ -0,0 +1,13 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/139570>.
+//! A coroutine with too many parameters should emit errors without an ICE.
+
+#![feature(coroutines)]
+
+fn main() {
+    #[coroutine]
+    |(1, 42), ()| {
+        //~^ ERROR too many parameters for a coroutine
+        //~| ERROR refutable pattern in closure argument
+        yield
+    };
+}

tests/ui/coroutine/too-many-parameters-ice.rs

@@ -0,0 +1,18 @@
+error[E0628]: too many parameters for a coroutine (expected 0 or 1 parameters)
+  --> $DIR/too-many-parameters-ice.rs:8:5
+   |
+LL |     |(1, 42), ()| {
+   |     ^^^^^^^^^^^^^
+
+error[E0005]: refutable pattern in closure argument
+  --> $DIR/too-many-parameters-ice.rs:8:6
+   |
+LL |     |(1, 42), ()| {
+   |      ^^^^^^^ patterns `(i32::MIN..=0_i32, _)` and `(2_i32..=i32::MAX, _)` not covered
+   |
+   = note: the matched value is of type `(i32, i32)`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0005, E0628.
+For more information about an error, try `rustc --explain E0005`.