Rename ensure_forwards_result_if_red to return_result_from_ensure_ok

Author: Zalathar

compiler/rustc_macros/src/query.rs

@@ -118,11 +118,17 @@ struct QueryModifiers {
     /// Generate a `feed` method to set the query's value from another query.
     feedable: Option<Ident>,
 
-    /// Forward the result on ensure if the query gets recomputed, and
-    /// return `Ok(())` otherwise. Only applicable to queries returning
-    /// `Result<T, ErrorGuaranteed>`. The `T` is not returned from `ensure`
-    /// invocations.
-    ensure_forwards_result_if_red: Option<Ident>,
+    /// When this query is called via `tcx.ensure_ok()`, it returns
+    /// `Result<(), ErrorGuaranteed>` instead of `()`. If the query needs to
+    /// be executed, and that execution returns an error, the error result is
+    /// returned to the caller.
+    ///
+    /// If execution is skipped, a synthetic `Ok(())` is returned, on the
+    /// assumption that a query with all-green inputs must have succeeded.
+    ///
+    /// Can only be applied to queries with a return value of
+    /// `Result<_, ErrorGuaranteed>`.
+    return_result_from_ensure_ok: Option<Ident>,
 }
 
 fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
@@ -138,7 +144,7 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
     let mut depth_limit = None;
     let mut separate_provide_extern = None;
     let mut feedable = None;
-    let mut ensure_forwards_result_if_red = None;
+    let mut return_result_from_ensure_ok = None;
 
     while !input.is_empty() {
         let modifier: Ident = input.parse()?;
@@ -200,8 +206,8 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
             try_insert!(separate_provide_extern = modifier);
         } else if modifier == "feedable" {
             try_insert!(feedable = modifier);
-        } else if modifier == "ensure_forwards_result_if_red" {
-            try_insert!(ensure_forwards_result_if_red = modifier);
+        } else if modifier == "return_result_from_ensure_ok" {
+            try_insert!(return_result_from_ensure_ok = modifier);
         } else {
             return Err(Error::new(modifier.span(), "unknown query modifier"));
         }
@@ -222,7 +228,7 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
         depth_limit,
         separate_provide_extern,
         feedable,
-        ensure_forwards_result_if_red,
+        return_result_from_ensure_ok,
     })
 }
 
@@ -354,7 +360,7 @@ pub(super) fn rustc_queries(input: TokenStream) -> TokenStream {
             eval_always,
             depth_limit,
             separate_provide_extern,
-            ensure_forwards_result_if_red,
+            return_result_from_ensure_ok,
         );
 
         if modifiers.cache.is_some() {

compiler/rustc_middle/src/query/mod.rs

@@ -1087,15 +1087,15 @@ rustc_queries! {
 
     query check_mod_type_wf(key: LocalModDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that types are well-formed in {}", describe_as_module(key, tcx) }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     /// Caches `CoerceUnsized` kinds for impls on custom types.
     query coerce_unsized_info(key: DefId) -> Result<ty::adjustment::CoerceUnsizedInfo, ErrorGuaranteed> {
         desc { |tcx| "computing CoerceUnsized info for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     query typeck(key: LocalDefId) -> &'tcx ty::TypeckResults<'tcx> {
@@ -1110,7 +1110,7 @@ rustc_queries! {
 
     query coherent_trait(def_id: DefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "coherence checking all impls of trait `{}`", tcx.def_path_str(def_id) }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     /// Borrow-checks the function body. If this is a closure, returns
@@ -1140,7 +1140,7 @@ rustc_queries! {
     /// </div>
     query crate_inherent_impls_validity_check(_: ()) -> Result<(), ErrorGuaranteed> {
         desc { "check for inherent impls that should not be defined in crate" }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     /// Checks all types in the crate for overlap in their inherent impls. Reports errors.
@@ -1152,7 +1152,7 @@ rustc_queries! {
     /// </div>
     query crate_inherent_impls_overlap_check(_: ()) -> Result<(), ErrorGuaranteed> {
         desc { "check for overlap between inherent impls defined in this crate" }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     /// Checks whether all impls in the crate pass the overlap check, returning
@@ -1162,7 +1162,7 @@ rustc_queries! {
             "checking whether impl `{}` follows the orphan rules",
             tcx.def_path_str(key),
         }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     /// Check whether the function has any recursion that could cause the inliner to trigger
@@ -1479,7 +1479,7 @@ rustc_queries! {
     query specialization_graph_of(trait_id: DefId) -> Result<&'tcx specialization_graph::Graph, ErrorGuaranteed> {
         desc { |tcx| "building specialization graph of trait `{}`", tcx.def_path_str(trait_id) }
         cache_on_disk_if { true }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
     query dyn_compatibility_violations(trait_id: DefId) -> &'tcx [DynCompatibilityViolation] {
         desc { |tcx| "determining dyn-compatibility of trait `{}`", tcx.def_path_str(trait_id) }
@@ -1715,12 +1715,12 @@ rustc_queries! {
 
     query check_well_formed(key: LocalDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that `{}` is well-formed", tcx.def_path_str(key) }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     query enforce_impl_non_lifetime_params_are_constrained(key: LocalDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that `{}`'s generics are constrained by the impl header", tcx.def_path_str(key) }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     // The `DefId`s of all non-generic functions and statics in the given crate
@@ -2442,7 +2442,7 @@ rustc_queries! {
     /// Any other def id will ICE.
     query compare_impl_item(key: LocalDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking assoc item `{}` is compatible with trait definition", tcx.def_path_str(key) }
-        ensure_forwards_result_if_red
+        return_result_from_ensure_ok
     }
 
     query deduced_param_attrs(def_id: DefId) -> &'tcx [ty::DeducedParamAttrs] {

compiler/rustc_middle/src/query/plumbing.rs

@@ -118,6 +118,12 @@ impl<'tcx> TyCtxt<'tcx> {
     ///
     /// Therefore, this call mode is not appropriate for callers that want to
     /// ensure that the query is _never_ executed in the future.
+    ///
+    /// ## `return_result_from_ensure_ok`
+    /// If a query has the `return_result_from_ensure_ok` modifier, calls via
+    /// `ensure_ok` will instead return `Result<(), ErrorGuaranteed>`. If the
+    /// query needs to be executed, and execution returns an error, that error
+    /// is returned to the caller.
     #[inline(always)]
     pub fn ensure_ok(self) -> TyCtxtEnsureOk<'tcx> {
         TyCtxtEnsureOk { tcx: self }
@@ -223,7 +229,7 @@ macro_rules! query_ensure {
     ([]$($args:tt)*) => {
         query_ensure($($args)*)
     };
-    ([(ensure_forwards_result_if_red) $($rest:tt)*]$($args:tt)*) => {
+    ([(return_result_from_ensure_ok) $($rest:tt)*]$($args:tt)*) => {
         query_ensure_error_guaranteed($($args)*).map(|_| ())
     };
     ([$other:tt $($modifiers:tt)*]$($args:tt)*) => {
@@ -282,7 +288,7 @@ macro_rules! ensure_ok_result {
     ( [] ) => {
         ()
     };
-    ( [(ensure_forwards_result_if_red) $($rest:tt)*] ) => {
+    ( [(return_result_from_ensure_ok) $($rest:tt)*] ) => {
         Result<(), ErrorGuaranteed>
     };
     ( [$other:tt $($modifiers:tt)*] ) => {