Add external macro guard and test middle MSRV

Author: Evan Typanski

clippy_lints/src/manual_rem_euclid.rs

@@ -4,7 +4,8 @@ use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{in_constant, meets_msrv, msrvs, path_to_local};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, Node, TyKind};
-use rustc_lint::{LateContext, LateLintPass};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
@@ -55,6 +56,10 @@ impl<'tcx> LateLintPass<'tcx> for ManualRemEuclid {
             return;
         }
 
+        if in_external_macro(cx.sess(), expr.span) {
+            return;
+        }
+
         if let ExprKind::Binary(op1, expr1, right) = expr.kind
             && op1.node == BinOpKind::Rem
             && let Some(const1) = check_for_unsigned_int_constant(cx, right)

tests/ui/auxiliary/macro_rules.rs

@@ -127,3 +127,11 @@ macro_rules! ptr_as_ptr_cast {
         $ptr as *const i32
     };
 }
+
+#[macro_export]
+macro_rules! manual_rem_euclid {
+    () => {
+        let value: i32 = 5;
+        let _: i32 = ((value % 4) + 4) % 4;
+    };
+}

tests/ui/manual_rem_euclid.fixed

@@ -1,7 +1,18 @@
 // run-rustfix
+// aux-build:macro_rules.rs
 
 #![warn(clippy::manual_rem_euclid)]
 
+#[macro_use]
+extern crate macro_rules;
+
+macro_rules! internal_rem_euclid {
+    () => {
+        let value: i32 = 5;
+        let _: i32 = value.rem_euclid(4);
+    };
+}
+
 fn main() {
     let value: i32 = 5;
 
@@ -25,6 +36,12 @@ fn main() {
     // For lint to apply the constant must always be on the RHS of the previous value for %
     let _: i32 = 4 % ((value % 4) + 4);
     let _: i32 = ((4 % value) + 4) % 4;
+
+    // Lint in internal macros
+    internal_rem_euclid!();
+
+    // Do not lint in external macros
+    manual_rem_euclid!();
 }
 
 // Should lint for params too

tests/ui/manual_rem_euclid.rs

@@ -1,7 +1,18 @@
 // run-rustfix
+// aux-build:macro_rules.rs
 
 #![warn(clippy::manual_rem_euclid)]
 
+#[macro_use]
+extern crate macro_rules;
+
+macro_rules! internal_rem_euclid {
+    () => {
+        let value: i32 = 5;
+        let _: i32 = ((value % 4) + 4) % 4;
+    };
+}
+
 fn main() {
     let value: i32 = 5;
 
@@ -25,6 +36,12 @@ fn main() {
     // For lint to apply the constant must always be on the RHS of the previous value for %
     let _: i32 = 4 % ((value % 4) + 4);
     let _: i32 = ((4 % value) + 4) % 4;
+
+    // Lint in internal macros
+    internal_rem_euclid!();
+
+    // Do not lint in external macros
+    manual_rem_euclid!();
 }
 
 // Should lint for params too

tests/ui/manual_rem_euclid.stderr

@@ -1,46 +1,57 @@
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:8:18
+  --> $DIR/manual_rem_euclid.rs:19:18
    |
 LL |     let _: i32 = ((value % 4) + 4) % 4;
    |                  ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
    |
    = note: `-D clippy::manual-rem-euclid` implied by `-D warnings`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:9:18
+  --> $DIR/manual_rem_euclid.rs:20:18
    |
 LL |     let _: i32 = (4 + (value % 4)) % 4;
    |                  ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:10:18
+  --> $DIR/manual_rem_euclid.rs:21:18
    |
 LL |     let _: i32 = (value % 4 + 4) % 4;
    |                  ^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:11:18
+  --> $DIR/manual_rem_euclid.rs:22:18
    |
 LL |     let _: i32 = (4 + value % 4) % 4;
    |                  ^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:12:22
+  --> $DIR/manual_rem_euclid.rs:23:22
    |
 LL |     let _: i32 = 1 + (4 + value % 4) % 4;
    |                      ^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:32:5
+  --> $DIR/manual_rem_euclid.rs:12:22
+   |
+LL |         let _: i32 = ((value % 4) + 4) % 4;
+   |                      ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `value.rem_euclid(4)`
+...
+LL |     internal_rem_euclid!();
+   |     ---------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `internal_rem_euclid` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: manual `rem_euclid` implementation
+  --> $DIR/manual_rem_euclid.rs:49:5
    |
 LL |     ((num % 4) + 4) % 4
    |     ^^^^^^^^^^^^^^^^^^^ help: consider using: `num.rem_euclid(4)`
 
 error: manual `rem_euclid` implementation
-  --> $DIR/manual_rem_euclid.rs:37:5
+  --> $DIR/manual_rem_euclid.rs:54:5
    |
 LL |     ((num % 4) + 4) % 4
    |     ^^^^^^^^^^^^^^^^^^^ help: consider using: `num.rem_euclid(4)`
 
-error: aborting due to 7 previous errors
+error: aborting due to 8 previous errors
 

tests/ui/min_rust_version_attr.rs

@@ -217,3 +217,12 @@ mod just_above_msrv {
         }
     }
 }
+
+mod const_rem_euclid {
+    #![feature(custom_inner_attributes)]
+    #![clippy::msrv = "1.50.0"]
+
+    pub const fn const_rem_euclid_4(num: i32) -> i32 {
+        ((num % 4) + 4) % 4
+    }
+}