Rollup merge of #132627 - adwinwhite:thir_body_cleanup, r=compiler-errors

cleanup: Remove outdated comment of `thir_body`

When typeck fails, `thir_body` returns `ErrorGuaranteed` rather than empty body.

No other code follows this outdated description except `check_unsafety`, which is also cleaned up in this PR.

Author: matthiaskrgr

compiler/rustc_middle/src/query/mod.rs

@@ -463,7 +463,7 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    /// Fetch the THIR for a given body. If typeck for that body failed, returns an empty `Thir`.
+    /// Fetch the THIR for a given body.
     query thir_body(key: LocalDefId) -> Result<(&'tcx Steal<thir::Thir<'tcx>>, thir::ExprId), ErrorGuaranteed> {
         // Perf tests revealed that hashing THIR is inefficient (see #85729).
         no_hash

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -1005,10 +1005,6 @@ pub(crate) fn check_unsafety(tcx: TyCtxt<'_>, def: LocalDefId) {
     // Runs all other queries that depend on THIR.
     tcx.ensure_with_value().mir_built(def);
     let thir = &thir.steal();
-    // If `thir` is empty, a type error occurred, skip this body.
-    if thir.exprs.is_empty() {
-        return;
-    }
 
     let hir_id = tcx.local_def_id_to_hir_id(def);
     let safety_context = tcx.hir().fn_sig_by_hir_id(hir_id).map_or(SafetyContext::Safe, |fn_sig| {