Auto merge of #9446 - mikerite:fix-9431-2, r=giraffate

Fix `range_{plus,minus}_one` bad suggestions

Fixes #9431.

The current `range_plus_one` and `range_minus_one` suggestions are completely incorrect when macros are involved.

This commit resolves this by disabling the lints for any range expression that is expanded from a macro. The reasons for this are that it is very difficult to create a correct suggestion in this case and that false negatives are less important for pedantic lints.

changelog: Fix `range_{plus,minus}_one` bad suggestions

Author: bors

clippy_lints/src/ranges.rs

@@ -350,21 +350,15 @@ fn check_range_bounds<'a>(cx: &'a LateContext<'_>, ex: &'a Expr<'_>) -> Option<R
 // exclusive range plus one: `x..(y+1)`
 fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
+        if expr.span.can_be_used_for_suggestions();
         if let Some(higher::Range {
             start,
             end: Some(end),
             limits: RangeLimits::HalfOpen
         }) = higher::Range::hir(expr);
         if let Some(y) = y_plus_one(cx, end);
         then {
-            let span = if expr.span.from_expansion() {
-                expr.span
-                    .ctxt()
-                    .outer_expn_data()
-                    .call_site
-            } else {
-                expr.span
-            };
+            let span = expr.span;
             span_lint_and_then(
                 cx,
                 RANGE_PLUS_ONE,
@@ -399,6 +393,7 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
 // inclusive range minus one: `x..=(y-1)`
 fn check_inclusive_range_minus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
+        if expr.span.can_be_used_for_suggestions();
         if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::Range::hir(expr);
         if let Some(y) = y_minus_one(cx, end);
         then {

tests/ui/range_plus_minus_one.fixed

@@ -6,6 +6,22 @@ fn f() -> usize {
     42
 }
 
+macro_rules! macro_plus_one {
+    ($m: literal) => {
+        for i in 0..$m + 1 {
+            println!("{}", i);
+        }
+    };
+}
+
+macro_rules! macro_minus_one {
+    ($m: literal) => {
+        for i in 0..=$m - 1 {
+            println!("{}", i);
+        }
+    };
+}
+
 #[warn(clippy::range_plus_one)]
 #[warn(clippy::range_minus_one)]
 fn main() {
@@ -39,4 +55,7 @@ fn main() {
 
     let mut vec: Vec<()> = std::vec::Vec::new();
     vec.drain(..);
+
+    macro_plus_one!(5);
+    macro_minus_one!(5);
 }

tests/ui/range_plus_minus_one.rs

@@ -6,6 +6,22 @@ fn f() -> usize {
     42
 }
 
+macro_rules! macro_plus_one {
+    ($m: literal) => {
+        for i in 0..$m + 1 {
+            println!("{}", i);
+        }
+    };
+}
+
+macro_rules! macro_minus_one {
+    ($m: literal) => {
+        for i in 0..=$m - 1 {
+            println!("{}", i);
+        }
+    };
+}
+
 #[warn(clippy::range_plus_one)]
 #[warn(clippy::range_minus_one)]
 fn main() {
@@ -39,4 +55,7 @@ fn main() {
 
     let mut vec: Vec<()> = std::vec::Vec::new();
     vec.drain(..);
+
+    macro_plus_one!(5);
+    macro_minus_one!(5);
 }

tests/ui/range_plus_minus_one.stderr

@@ -1,57 +1,57 @@
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:15:14
+  --> $DIR/range_plus_minus_one.rs:31:14
    |
 LL |     for _ in 0..3 + 1 {}
    |              ^^^^^^^^ help: use: `0..=3`
    |
    = note: `-D clippy::range-plus-one` implied by `-D warnings`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:18:14
+  --> $DIR/range_plus_minus_one.rs:34:14
    |
 LL |     for _ in 0..1 + 5 {}
    |              ^^^^^^^^ help: use: `0..=5`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:21:14
+  --> $DIR/range_plus_minus_one.rs:37:14
    |
 LL |     for _ in 1..1 + 1 {}
    |              ^^^^^^^^ help: use: `1..=1`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:27:14
+  --> $DIR/range_plus_minus_one.rs:43:14
    |
 LL |     for _ in 0..(1 + f()) {}
    |              ^^^^^^^^^^^^ help: use: `0..=f()`
 
 error: an exclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:31:13
+  --> $DIR/range_plus_minus_one.rs:47:13
    |
 LL |     let _ = ..=11 - 1;
    |             ^^^^^^^^^ help: use: `..11`
    |
    = note: `-D clippy::range-minus-one` implied by `-D warnings`
 
 error: an exclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:32:13
+  --> $DIR/range_plus_minus_one.rs:48:13
    |
 LL |     let _ = ..=(11 - 1);
    |             ^^^^^^^^^^^ help: use: `..11`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:33:13
+  --> $DIR/range_plus_minus_one.rs:49:13
    |
 LL |     let _ = (1..11 + 1);
    |             ^^^^^^^^^^^ help: use: `(1..=11)`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:34:13
+  --> $DIR/range_plus_minus_one.rs:50:13
    |
 LL |     let _ = (f() + 1)..(f() + 1);
    |             ^^^^^^^^^^^^^^^^^^^^ help: use: `((f() + 1)..=f())`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:38:14
+  --> $DIR/range_plus_minus_one.rs:54:14
    |
 LL |     for _ in 1..ONE + ONE {}
    |              ^^^^^^^^^^^^ help: use: `1..=ONE`