Auto merge of rust-lang#9389 - lukaslueg:penmacro, r=llogiq

Don't lint literal `None` from expansion

This addresses rust-lang/rust-clippy#9288 (comment): If the literal `None` is from expansion, we never lint. This is correct because e.g. replacing the call to `option_env!` with whatever that macro expanded to at the time of linting is certainly wrong.

changelog: Don't lint [`partialeq_to_none`] for macro-expansions

Author: bors

clippy_lints/src/partialeq_to_none.rs

@@ -53,7 +53,8 @@ impl<'tcx> LateLintPass<'tcx> for PartialeqToNone {
 
         // If the expression is a literal `Option::None`
         let is_none_ctor = |expr: &Expr<'_>| {
-            matches!(&peel_hir_expr_refs(expr).0.kind,
+            !expr.span.from_expansion()
+                && matches!(&peel_hir_expr_refs(expr).0.kind,
             ExprKind::Path(p) if is_lang_ctor(cx, p, LangItem::OptionNone))
         };
 

tests/ui/partialeq_to_none.fixed

@@ -26,6 +26,18 @@ fn optref() -> &'static &'static Option<()> {
     &&None
 }
 
+pub fn macro_expansion() {
+    macro_rules! foo {
+        () => {
+            None::<()>
+        };
+    }
+
+    let _ = foobar() == foo!();
+    let _ = foo!() == foobar();
+    let _ = foo!() == foo!();
+}
+
 fn main() {
     let x = Some(0);
 

tests/ui/partialeq_to_none.rs

@@ -26,6 +26,18 @@ fn optref() -> &'static &'static Option<()> {
     &&None
 }
 
+pub fn macro_expansion() {
+    macro_rules! foo {
+        () => {
+            None::<()>
+        };
+    }
+
+    let _ = foobar() == foo!();
+    let _ = foo!() == foobar();
+    let _ = foo!() == foo!();
+}
+
 fn main() {
     let x = Some(0);
 

tests/ui/partialeq_to_none.stderr

@@ -7,55 +7,55 @@ LL |     if f != None { "yay" } else { "nay" }
    = note: `-D clippy::partialeq-to-none` implied by `-D warnings`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:32:13
+  --> $DIR/partialeq_to_none.rs:44:13
    |
 LL |     let _ = x == None;
    |             ^^^^^^^^^ help: use `Option::is_none()` instead: `x.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:33:13
+  --> $DIR/partialeq_to_none.rs:45:13
    |
 LL |     let _ = x != None;
    |             ^^^^^^^^^ help: use `Option::is_some()` instead: `x.is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:34:13
+  --> $DIR/partialeq_to_none.rs:46:13
    |
 LL |     let _ = None == x;
    |             ^^^^^^^^^ help: use `Option::is_none()` instead: `x.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:35:13
+  --> $DIR/partialeq_to_none.rs:47:13
    |
 LL |     let _ = None != x;
    |             ^^^^^^^^^ help: use `Option::is_some()` instead: `x.is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:37:8
+  --> $DIR/partialeq_to_none.rs:49:8
    |
 LL |     if foobar() == None {}
    |        ^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `foobar().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:39:8
+  --> $DIR/partialeq_to_none.rs:51:8
    |
 LL |     if bar().ok() != None {}
    |        ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `bar().ok().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:41:13
+  --> $DIR/partialeq_to_none.rs:53:13
    |
 LL |     let _ = Some(1 + 2) != None;
    |             ^^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `Some(1 + 2).is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:43:13
+  --> $DIR/partialeq_to_none.rs:55:13
    |
 LL |     let _ = { Some(0) } == None;
    |             ^^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `{ Some(0) }.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:45:13
+  --> $DIR/partialeq_to_none.rs:57:13
    |
 LL |       let _ = {
    |  _____________^
@@ -77,31 +77,31 @@ LL ~     }.is_some();
    |
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:55:13
+  --> $DIR/partialeq_to_none.rs:67:13
    |
 LL |     let _ = optref() == &&None;
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `optref().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:56:13
+  --> $DIR/partialeq_to_none.rs:68:13
    |
 LL |     let _ = &&None != optref();
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `optref().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:57:13
+  --> $DIR/partialeq_to_none.rs:69:13
    |
 LL |     let _ = **optref() == None;
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `optref().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:58:13
+  --> $DIR/partialeq_to_none.rs:70:13
    |
 LL |     let _ = &None != *optref();
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `optref().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:61:13
+  --> $DIR/partialeq_to_none.rs:73:13
    |
 LL |     let _ = None != *x;
    |             ^^^^^^^^^^ help: use `Option::is_some()` instead: `(*x).is_some()`