diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index 2a767646eafe..04af1eaf67b6 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -539,11 +539,11 @@ pub fn compile_declarative_macro(
         None => {}
     }
 
-    // Compute the spans of the macro rules
-    // We only take the span of the lhs here,
-    // so that the spans of created warnings are smaller.
+    // Compute the spans of the macro rules for unused rule linting.
+    // To avoid warning noise, only consider the rules of this
+    // macro for the lint, if all rules are valid.
     // Also, we are only interested in non-foreign macros.
-    let rule_spans = if def.id != DUMMY_NODE_ID {
+    let rule_spans = if valid && def.id != DUMMY_NODE_ID {
         lhses
             .iter()
             .zip(rhses.iter())
@@ -551,6 +551,8 @@ pub fn compile_declarative_macro(
             // If the rhs contains an invocation like compile_error!,
             // don't consider the rule for the unused rule lint.
             .filter(|(_idx, (_lhs, rhs))| !has_compile_error_macro(rhs))
+            // We only take the span of the lhs here,
+            // so that the spans of created warnings are smaller.
             .map(|(idx, (lhs, _rhs))| (idx, lhs.span()))
             .collect::<Vec<_>>()
     } else {
diff --git a/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.rs b/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.rs
new file mode 100644
index 000000000000..a826026ec405
--- /dev/null
+++ b/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.rs
@@ -0,0 +1,11 @@
+#![deny(unused_macro_rules)]
+
+macro_rules! foo {
+    (v) => {};
+    (w) => {};
+    () => 0; //~ ERROR: macro rhs must be delimited
+}
+
+fn main() {
+    foo!(v);
+}
diff --git a/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.stderr b/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.stderr
new file mode 100644
index 000000000000..797c867103f0
--- /dev/null
+++ b/src/test/ui/lint/unused/unused-macro-rules-malformed-rule.stderr
@@ -0,0 +1,8 @@
+error: macro rhs must be delimited
+  --> $DIR/unused-macro-rules-malformed-rule.rs:6:11
+   |
+LL |     () => 0;
+   |           ^
+
+error: aborting due to previous error
+