Fix ICE with -Zunpretty=hir,typed when an expression occurs in a function signature

Author: FabianWolff

compiler/rustc_driver/src/pretty.rs

@@ -293,18 +293,6 @@ struct TypedAnnotation<'tcx> {
     maybe_typeck_results: Cell<Option<&'tcx ty::TypeckResults<'tcx>>>,
 }
 
-impl<'tcx> TypedAnnotation<'tcx> {
-    /// Gets the type-checking results for the current body.
-    /// As this will ICE if called outside bodies, only call when working with
-    /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies).
-    #[track_caller]
-    fn typeck_results(&self) -> &'tcx ty::TypeckResults<'tcx> {
-        self.maybe_typeck_results
-            .get()
-            .expect("`TypedAnnotation::typeck_results` called outside of body")
-    }
-}
-
 impl<'tcx> HirPrinterSupport<'tcx> for TypedAnnotation<'tcx> {
     fn sess(&self) -> &Session {
         &self.tcx.sess
@@ -336,10 +324,24 @@ impl<'tcx> pprust_hir::PpAnn for TypedAnnotation<'tcx> {
     }
     fn post(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
         if let pprust_hir::AnnNode::Expr(expr) = node {
-            s.s.space();
-            s.s.word("as");
-            s.s.space();
-            s.s.word(self.typeck_results().expr_ty(expr).to_string());
+            let typeck_results =
+                self.maybe_typeck_results.get().or_else(|| {
+                    if let Some(body_id) = self.tcx.hir().maybe_body_owned_by(
+                        self.tcx.hir().local_def_id_to_hir_id(expr.hir_id.owner),
+                    ) {
+                        Some(self.tcx.typeck_body(body_id))
+                    } else {
+                        None
+                    }
+                });
+
+            if let Some(typeck_results) = typeck_results {
+                s.s.space();
+                s.s.word("as");
+                s.s.space();
+                s.s.word(typeck_results.expr_ty(expr).to_string());
+            }
+
             s.pclose();
         }
     }

src/test/ui/unpretty-expr-fn-arg.rs

@@ -0,0 +1,13 @@
+// Regression test for the ICE described in #82328. The pretty-printer for
+// compile-flags: -Zunpretty=hir,typed
+// would previously retrieve type-checking results when entering a body,
+// which means that type information was not available for expressions
+// occurring in function signatures, as in the `foo` example below, leading
+// to an ICE.
+
+// check-pass
+#![allow(dead_code)]
+
+fn main() {}
+
+fn foo(-128..=127: i8) {}

src/test/ui/unpretty-expr-fn-arg.stdout

@@ -0,0 +1,17 @@
+// Regression test for the ICE described in #82328. The pretty-printer for
+// compile-flags: -Zunpretty=hir,typed
+// would previously retrieve type-checking results when entering a body,
+// which means that type information was not available for expressions
+// occurring in function signatures, as in the `foo` example below, leading
+// to an ICE.
+
+// check-pass
+#![allow(dead_code)]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+
+fn main() ({ } as ())
+
+fn foo((-(128 as i8) as i8) ...(127 as i8): i8) ({ } as ())