reviews

Author: BoxyUwU

compiler/rustc_session/src/config.rs

@@ -748,7 +748,7 @@ pub enum TraitSolver {
 #[derive(Default, Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub enum SolverProofTreeCondition {
     #[default]
-    Never,
+    OnRequest,
     Always,
     OnError,
 }

compiler/rustc_session/src/options.rs

@@ -418,7 +418,8 @@ mod desc {
         "a `,` separated combination of `bti`, `b-key`, `pac-ret`, or `leaf`";
     pub const parse_proc_macro_execution_strategy: &str =
         "one of supported execution strategies (`same-thread`, or `cross-thread`)";
-    pub const parse_solver_proof_tree_condition: &str = "one of: `always`, `never`, `on_error`";
+    pub const parse_solver_proof_tree_condition: &str =
+        "one of: `always`, `on-request`, `on-error`";
 }
 
 mod parse {
@@ -1246,7 +1247,7 @@ mod parse {
     ) -> bool {
         match v {
             None | Some("always") => *slot = SolverProofTreeCondition::Always,
-            Some("never") => *slot = SolverProofTreeCondition::Never,
+            Some("on-request") => *slot = SolverProofTreeCondition::OnRequest,
             Some("on-error") => *slot = SolverProofTreeCondition::OnError,
             _ => return false,
         };
@@ -1477,8 +1478,9 @@ options! {
         "output statistics about monomorphization collection"),
     dump_mono_stats_format: DumpMonoStatsFormat = (DumpMonoStatsFormat::Markdown, parse_dump_mono_stats, [UNTRACKED],
         "the format to use for -Z dump-mono-stats (`markdown` (default) or `json`)"),
-    dump_solver_proof_tree: SolverProofTreeCondition = (SolverProofTreeCondition::Never, parse_solver_proof_tree_condition, [UNTRACKED],
-        "dump a proof tree for every goal evaluated by the new trait solver. The default is `always`"),
+    dump_solver_proof_tree: SolverProofTreeCondition = (SolverProofTreeCondition::OnRequest, parse_solver_proof_tree_condition, [UNTRACKED],
+        "dump a proof tree for every goal evaluated by the new trait solver. If the flag is specified without any options after it
+        then it defaults to `always`. If the flag is not specified at all it defaults to `on-request`."),
     dump_solver_proof_tree_uses_cache: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
         "determines whether proof tree generation uses the global cache"),
     dwarf_version: Option<u32> = (None, parse_opt_number, [TRACKED],

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -196,9 +196,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                 }
 
                 (_, None, GenerateProofTree::Yes(_)) => generate_proof_tree,
-                // `Never` is kind of weird- it doesn't actually force us to not generate proof trees
-                // its just the default setting for rustflags forced proof tree generation.
-                (SolverProofTreeCondition::Never, _, _) => generate_proof_tree,
+                (SolverProofTreeCondition::OnRequest, _, _) => generate_proof_tree,
                 (SolverProofTreeCondition::OnError, _, _) => generate_proof_tree,
             };