Auto merge of #11996 - J-ZhengLi:issue11992, r=xFrednet,ARandomDev99

fix suggestion for [`len_zero`] with macros

fixes: #11992

changelog: fix suggestion for [`len_zero`] with macros

3 files changed, 93 insertions, 1 deletions

diff --git a/tests/ui/len_zero.fixed b/tests/ui/len_zero.fixed
index c16d7a26616..27319d9c20e 100644
--- a/tests/ui/len_zero.fixed
+++ b/tests/ui/len_zero.fixed
@@ -189,3 +189,40 @@ fn main() {
 fn test_slice(b: &[u8]) {
     if !b.is_empty() {}
 }
+
+// issue #11992
+fn binop_with_macros() {
+    macro_rules! len {
+        ($seq:ident) => {
+            $seq.len()
+        };
+    }
+
+    macro_rules! compare_to {
+        ($val:literal) => {
+            $val
+        };
+        ($val:expr) => {{ $val }};
+    }
+
+    macro_rules! zero {
+        () => {
+            0
+        };
+    }
+
+    let has_is_empty = HasIsEmpty;
+    // Don't lint, suggesting changes might break macro compatibility.
+    (len!(has_is_empty) > 0).then(|| println!("This can happen."));
+    // Don't lint, suggesting changes might break macro compatibility.
+    if len!(has_is_empty) == 0 {}
+    // Don't lint
+    if has_is_empty.len() == compare_to!(if true { 0 } else { 1 }) {}
+    // This is fine
+    if has_is_empty.len() == compare_to!(1) {}
+
+    if has_is_empty.is_empty() {}
+    if has_is_empty.is_empty() {}
+
+    (!has_is_empty.is_empty()).then(|| println!("This can happen."));
+}
diff --git a/tests/ui/len_zero.rs b/tests/ui/len_zero.rs
index 5c49a5abf81..03c05bc6ed7 100644
--- a/tests/ui/len_zero.rs
+++ b/tests/ui/len_zero.rs
@@ -189,3 +189,40 @@ fn main() {
 fn test_slice(b: &[u8]) {
     if b.len() != 0 {}
 }
+
+// issue #11992
+fn binop_with_macros() {
+    macro_rules! len {
+        ($seq:ident) => {
+            $seq.len()
+        };
+    }
+
+    macro_rules! compare_to {
+        ($val:literal) => {
+            $val
+        };
+        ($val:expr) => {{ $val }};
+    }
+
+    macro_rules! zero {
+        () => {
+            0
+        };
+    }
+
+    let has_is_empty = HasIsEmpty;
+    // Don't lint, suggesting changes might break macro compatibility.
+    (len!(has_is_empty) > 0).then(|| println!("This can happen."));
+    // Don't lint, suggesting changes might break macro compatibility.
+    if len!(has_is_empty) == 0 {}
+    // Don't lint
+    if has_is_empty.len() == compare_to!(if true { 0 } else { 1 }) {}
+    // This is fine
+    if has_is_empty.len() == compare_to!(1) {}
+
+    if has_is_empty.len() == compare_to!(0) {}
+    if has_is_empty.len() == zero!() {}
+
+    (compare_to!(0) < has_is_empty.len()).then(|| println!("This can happen."));
+}
diff --git a/tests/ui/len_zero.stderr b/tests/ui/len_zero.stderr
index dd07a85d62c..5c849a2aca6 100644
--- a/tests/ui/len_zero.stderr
+++ b/tests/ui/len_zero.stderr
@@ -142,5 +142,23 @@ error: length comparison to zero
 LL |     if b.len() != 0 {}
    |        ^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!b.is_empty()`
 
-error: aborting due to 23 previous errors
+error: length comparison to zero
+  --> tests/ui/len_zero.rs:224:8
+   |
+LL |     if has_is_empty.len() == compare_to!(0) {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
+
+error: length comparison to zero
+  --> tests/ui/len_zero.rs:225:8
+   |
+LL |     if has_is_empty.len() == zero!() {}
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
+
+error: length comparison to zero
+  --> tests/ui/len_zero.rs:227:6
+   |
+LL |     (compare_to!(0) < has_is_empty.len()).then(|| println!("This can happen."));
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
+
+error: aborting due to 26 previous errors