From 9308401df57318cf3b3ad72bd3674516fe9d1c6c Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Tue, 23 Jul 2024 14:59:01 +0200
Subject: [PATCH] tracing: debug to trace

---
 compiler/rustc_type_ir/src/binder.rs | 24 ++++++++----------------
 compiler/rustc_type_ir/src/fold.rs   | 11 +++++------
 2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/compiler/rustc_type_ir/src/binder.rs b/compiler/rustc_type_ir/src/binder.rs
index c1f6fb36324e..8797288070e7 100644
--- a/compiler/rustc_type_ir/src/binder.rs
+++ b/compiler/rustc_type_ir/src/binder.rs
@@ -8,7 +8,7 @@ use derive_where::derive_where;
 use rustc_macros::{HashStable_NoContext, TyDecodable, TyEncodable};
 #[cfg(feature = "nightly")]
 use rustc_serialize::Decodable;
-use tracing::debug;
+use tracing::instrument;
 
 use crate::data_structures::SsoHashSet;
 use crate::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
@@ -831,28 +831,20 @@ impl<'a, I: Interner> ArgFolder<'a, I> {
     /// As indicated in the diagram, here the same type `&'a i32` is instantiated once, but in the
     /// first case we do not increase the De Bruijn index and in the second case we do. The reason
     /// is that only in the second case have we passed through a fn binder.
+    #[instrument(level = "trace", skip(self), fields(binders_passed = self.binders_passed), ret)]
     fn shift_vars_through_binders<T: TypeFoldable<I>>(&self, val: T) -> T {
-        debug!(
-            "shift_vars(val={:?}, binders_passed={:?}, has_escaping_bound_vars={:?})",
-            val,
-            self.binders_passed,
-            val.has_escaping_bound_vars()
-        );
-
         if self.binders_passed == 0 || !val.has_escaping_bound_vars() {
-            return val;
+            val
+        } else {
+            ty::fold::shift_vars(self.cx, val, self.binders_passed)
         }
-
-        let result = ty::fold::shift_vars(TypeFolder::cx(self), val, self.binders_passed);
-        debug!("shift_vars: shifted result = {:?}", result);
-
-        result
     }
 
     fn shift_region_through_binders(&self, region: I::Region) -> I::Region {
         if self.binders_passed == 0 || !region.has_escaping_bound_vars() {
-            return region;
+            region
+        } else {
+            ty::fold::shift_region(self.cx, region, self.binders_passed)
         }
-        ty::fold::shift_region(self.cx, region, self.binders_passed)
     }
 }
diff --git a/compiler/rustc_type_ir/src/fold.rs b/compiler/rustc_type_ir/src/fold.rs
index d37bacc7d359..8e3534b0e9eb 100644
--- a/compiler/rustc_type_ir/src/fold.rs
+++ b/compiler/rustc_type_ir/src/fold.rs
@@ -48,7 +48,7 @@
 use std::mem;
 
 use rustc_index::{Idx, IndexVec};
-use tracing::debug;
+use tracing::instrument;
 
 use crate::data_structures::Lrc;
 use crate::inherent::*;
@@ -417,15 +417,14 @@ pub fn shift_region<I: Interner>(cx: I, region: I::Region, amount: u32) -> I::Re
     }
 }
 
+#[instrument(level = "trace", skip(cx), ret)]
 pub fn shift_vars<I: Interner, T>(cx: I, value: T, amount: u32) -> T
 where
     T: TypeFoldable<I>,
 {
-    debug!("shift_vars(value={:?}, amount={})", value, amount);
-
     if amount == 0 || !value.has_escaping_bound_vars() {
-        return value;
+        value
+    } else {
+        value.fold_with(&mut Shifter::new(cx, amount))
     }
-
-    value.fold_with(&mut Shifter::new(cx, amount))
 }