Also check code generated by macros

Author: GuillaumeGomez

clippy_lints/src/unconditional_recursion.rs

@@ -66,10 +66,6 @@ impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
         method_span: Span,
         def_id: LocalDefId,
     ) {
-        // We don't check code generated from (proc) macro.
-        if method_span.from_expansion() {
-            return;
-        }
         if let FnKind::Method(name, _) = kind
             && let [self_arg, other_arg] = cx
                 .tcx

tests/ui/unconditional_recursion.rs

@@ -123,6 +123,33 @@ impl PartialEq for S3 {
     }
 }
 
+#[derive(PartialEq)]
+struct Bar<T: PartialEq>(T);
+
+struct S4;
+
+impl PartialEq for S4 {
+    fn eq(&self, other: &Self) -> bool {
+        // No warning here.
+        Bar(self) == Bar(other)
+    }
+}
+
+macro_rules! impl_partial_eq {
+    ($ty:ident) => {
+        impl PartialEq for $ty {
+            fn eq(&self, other: &Self) -> bool {
+                self == other
+            }
+        }
+    }
+}
+
+struct S5;
+
+impl_partial_eq!(S5);
+//~^ ERROR: function cannot return without recursing
+
 fn main() {
     // test code goes here
 }

tests/ui/unconditional_recursion.stderr

@@ -298,5 +298,26 @@ error: equal expressions as operands to `==`
 LL |         self == self
    |         ^^^^^^^^^^^^
 
-error: aborting due to 26 previous errors
+error: function cannot return without recursing
+  --> $DIR/unconditional_recursion.rs:141:13
+   |
+LL | /             fn eq(&self, other: &Self) -> bool {
+LL | |                 self == other
+LL | |             }
+   | |_____________^
+...
+LL |   impl_partial_eq!(S5);
+   |   -------------------- in this macro invocation
+   |
+note: recursive call site
+  --> $DIR/unconditional_recursion.rs:142:17
+   |
+LL |                 self == other
+   |                 ^^^^^^^^^^^^^
+...
+LL | impl_partial_eq!(S5);
+   | -------------------- in this macro invocation
+   = note: this error originates in the macro `impl_partial_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 27 previous errors