diff --git a/src/librustc_session/session.rs b/src/librustc_session/session.rs
index 4b1cc71c822f3..b39b15dc24428 100644
--- a/src/librustc_session/session.rs
+++ b/src/librustc_session/session.rs
@@ -808,7 +808,7 @@ impl Session {
                 let mut fuel = self.optimization_fuel.lock();
                 ret = fuel.remaining != 0;
                 if fuel.remaining == 0 && !fuel.out_of_fuel {
-                    eprintln!("optimization-fuel-exhausted: {}", msg());
+                    self.warn(&format!("optimization-fuel-exhausted: {}", msg()));
                     fuel.out_of_fuel = true;
                 } else if fuel.remaining > 0 {
                     fuel.remaining -= 1;
diff --git a/src/test/ui/optimization-fuel-0.rs b/src/test/ui/optimization-fuel-0.rs
index f86972b734826..a97c5750f94c3 100644
--- a/src/test/ui/optimization-fuel-0.rs
+++ b/src/test/ui/optimization-fuel-0.rs
@@ -4,8 +4,7 @@
 
 use std::mem::size_of;
 
-// (#55495: The --error-format is to sidestep an issue in our test harness)
-// compile-flags: --error-format human -Z fuel=foo=0
+// compile-flags: -Z fuel=foo=0
 
 struct S1(u8, u16, u8);
 struct S2(u8, u16, u8);
diff --git a/src/test/ui/optimization-fuel-0.stderr b/src/test/ui/optimization-fuel-0.stderr
index 3ad405b2b50ff..f0e2ebfc37a37 100644
--- a/src/test/ui/optimization-fuel-0.stderr
+++ b/src/test/ui/optimization-fuel-0.stderr
@@ -1 +1,4 @@
-optimization-fuel-exhausted: Reorder fields of "S1"
+warning: optimization-fuel-exhausted: Reorder fields of "S1"
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/optimization-fuel-1.rs b/src/test/ui/optimization-fuel-1.rs
index 98283066361c2..a09f91c68abe7 100644
--- a/src/test/ui/optimization-fuel-1.rs
+++ b/src/test/ui/optimization-fuel-1.rs
@@ -4,8 +4,7 @@
 
 use std::mem::size_of;
 
-// (#55495: The --error-format is to sidestep an issue in our test harness)
-// compile-flags: --error-format human -Z fuel=foo=1
+// compile-flags: -Z fuel=foo=1
 
 struct S1(u8, u16, u8);
 struct S2(u8, u16, u8);
diff --git a/src/test/ui/optimization-fuel-1.stderr b/src/test/ui/optimization-fuel-1.stderr
index 197e45219c3f8..53eafb05830cb 100644
--- a/src/test/ui/optimization-fuel-1.stderr
+++ b/src/test/ui/optimization-fuel-1.stderr
@@ -1 +1,4 @@
-optimization-fuel-exhausted: Reorder fields of "S2"
+warning: optimization-fuel-exhausted: Reorder fields of "S2"
+
+warning: 1 warning emitted
+