create module so that RUSTC_LOG can filter to just proof trees

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -164,7 +164,8 @@ impl<'tcx> InferCtxtEvalExt<'tcx> for InferCtxt<'tcx> {
 
         let tree = ecx.inspect.finalize();
         if let Some(tree) = &tree {
-            debug!(?tree);
+            // module to allow more granular RUSTC_LOG filtering to just proof tree output
+            super::inspect::dump::print_tree(tree);
         }
 
         assert!(

compiler/rustc_trait_selection/src/solve/inspect.rs

@@ -10,6 +10,8 @@ use rustc_middle::{
     ty,
 };
 
+pub mod dump;
+
 #[derive(Eq, PartialEq, Debug, Hash, HashStable)]
 pub struct WipGoalEvaluation<'tcx> {
     pub uncanonicalized_goal: Goal<'tcx, ty::Predicate<'tcx>>,

compiler/rustc_trait_selection/src/solve/inspect/dump.rs

@@ -0,0 +1,5 @@
+use rustc_middle::traits::solve::inspect::GoalEvaluation;
+
+pub fn print_tree(tree: &GoalEvaluation<'_>) {
+    debug!(?tree);
+}