Merge pull request #2364 from flip1995/precedence

Add macro check to precedence lint

clippy_lints/src/precedence.rs

@@ -1,7 +1,7 @@
 use rustc::lint::*;
 use syntax::ast::*;
 use syntax::codemap::Spanned;
-use utils::{snippet, span_lint_and_sugg};
+use utils::{in_macro, snippet, span_lint_and_sugg};
 
 /// **What it does:** Checks for operations where precedence may be unclear
 /// and suggests to add parentheses. Currently it catches the following:
@@ -37,6 +37,10 @@ impl LintPass for Precedence {
 
 impl EarlyLintPass for Precedence {
     fn check_expr(&mut self, cx: &EarlyContext, expr: &Expr) {
+        if in_macro(expr.span) {
+            return;
+        }
+
         if let ExprKind::Binary(Spanned { node: op, .. }, ref left, ref right) = expr.node {
             let span_sugg = |expr: &Expr, sugg| {
                 span_lint_and_sugg(

tests/ui/precedence.rs

@@ -4,6 +4,16 @@
 #[warn(precedence)]
 #[allow(identity_op)]
 #[allow(eq_op)]
+
+macro_rules! trip {
+   ($a:expr) => {
+    match $a & 0b1111_1111i8 {
+        0 => println!("a is zero ({})", $a),
+        _ => println!("a is {}", $a),
+    }
+   };
+}
+
 fn main() {
     1 << 2 + 3;
     1 + 2 << 3;
@@ -22,4 +32,7 @@ fn main() {
     let _ = -(1f32).abs();
     let _ = -(1i32.abs());
     let _ = -(1f32.abs());
+
+    let b = 3;
+    trip!(b * 8);
 }

tests/ui/precedence.stderr

@@ -1,57 +1,57 @@
 error: operator precedence can trip the unwary
- --> $DIR/precedence.rs:8:5
-  |
-8 |     1 << 2 + 3;
-  |     ^^^^^^^^^^ help: consider parenthesizing your expression: `1 << (2 + 3)`
-  |
-  = note: `-D precedence` implied by `-D warnings`
-
-error: operator precedence can trip the unwary
- --> $DIR/precedence.rs:9:5
-  |
-9 |     1 + 2 << 3;
-  |     ^^^^^^^^^^ help: consider parenthesizing your expression: `(1 + 2) << 3`
-
-error: operator precedence can trip the unwary
-  --> $DIR/precedence.rs:10:5
+  --> $DIR/precedence.rs:18:5
    |
-10 |     4 >> 1 + 1;
+18 |     1 << 2 + 3;
+   |     ^^^^^^^^^^ help: consider parenthesizing your expression: `1 << (2 + 3)`
+   |
+   = note: `-D precedence` implied by `-D warnings`
+
+error: operator precedence can trip the unwary
+  --> $DIR/precedence.rs:19:5
+   |
+19 |     1 + 2 << 3;
+   |     ^^^^^^^^^^ help: consider parenthesizing your expression: `(1 + 2) << 3`
+
+error: operator precedence can trip the unwary
+  --> $DIR/precedence.rs:20:5
+   |
+20 |     4 >> 1 + 1;
    |     ^^^^^^^^^^ help: consider parenthesizing your expression: `4 >> (1 + 1)`
 
 error: operator precedence can trip the unwary
-  --> $DIR/precedence.rs:11:5
+  --> $DIR/precedence.rs:21:5
    |
-11 |     1 + 3 >> 2;
+21 |     1 + 3 >> 2;
    |     ^^^^^^^^^^ help: consider parenthesizing your expression: `(1 + 3) >> 2`
 
 error: operator precedence can trip the unwary
-  --> $DIR/precedence.rs:12:5
+  --> $DIR/precedence.rs:22:5
    |
-12 |     1 ^ 1 - 1;
+22 |     1 ^ 1 - 1;
    |     ^^^^^^^^^ help: consider parenthesizing your expression: `1 ^ (1 - 1)`
 
 error: operator precedence can trip the unwary
-  --> $DIR/precedence.rs:13:5
+  --> $DIR/precedence.rs:23:5
    |
-13 |     3 | 2 - 1;
+23 |     3 | 2 - 1;
    |     ^^^^^^^^^ help: consider parenthesizing your expression: `3 | (2 - 1)`
 
 error: operator precedence can trip the unwary
-  --> $DIR/precedence.rs:14:5
+  --> $DIR/precedence.rs:24:5
    |
-14 |     3 & 5 - 2;
+24 |     3 & 5 - 2;
    |     ^^^^^^^^^ help: consider parenthesizing your expression: `3 & (5 - 2)`
 
 error: unary minus has lower precedence than method call
-  --> $DIR/precedence.rs:15:5
+  --> $DIR/precedence.rs:25:5
    |
-15 |     -1i32.abs();
+25 |     -1i32.abs();
    |     ^^^^^^^^^^^ help: consider adding parentheses to clarify your intent: `-(1i32.abs())`
 
 error: unary minus has lower precedence than method call
-  --> $DIR/precedence.rs:16:5
+  --> $DIR/precedence.rs:26:5
    |
-16 |     -1f32.abs();
+26 |     -1f32.abs();
    |     ^^^^^^^^^^^ help: consider adding parentheses to clarify your intent: `-(1f32.abs())`
 
 error: aborting due to 9 previous errors