Preserve literals and range kinds in manual_range_patterns

clippy_lints/src/manual_range_patterns.rs

@@ -1,4 +1,5 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_opt;
 use rustc_ast::LitKind;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
@@ -6,6 +7,7 @@ use rustc_hir::{Expr, ExprKind, PatKind, RangeEnd, UnOp};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::{Span, DUMMY_SP};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -49,6 +51,29 @@ fn expr_as_i128(expr: &Expr<'_>) -> Option<i128> {
     }
 }
 
+#[derive(Copy, Clone)]
+struct Num {
+    val: i128,
+    span: Span,
+}
+
+impl Num {
+    fn new(expr: &Expr<'_>) -> Option<Self> {
+        Some(Self {
+            val: expr_as_i128(expr)?,
+            span: expr.span,
+        })
+    }
+
+    fn dummy(val: i128) -> Self {
+        Self { val, span: DUMMY_SP }
+    }
+
+    fn min(self, other: Self) -> Self {
+        if self.val < other.val { self } else { other }
+    }
+}
+
 impl LateLintPass<'_> for ManualRangePatterns {
     fn check_pat(&mut self, cx: &LateContext<'_>, pat: &'_ rustc_hir::Pat<'_>) {
         if in_external_macro(cx.sess(), pat.span) {
@@ -56,71 +81,83 @@ impl LateLintPass<'_> for ManualRangePatterns {
         }
 
         // a pattern like 1 | 2 seems fine, lint if there are at least 3 alternatives
+        // or at least one range
         if let PatKind::Or(pats) = pat.kind
-            && pats.len() >= 3
+            && (pats.len() >= 3 || pats.iter().any(|p| matches!(p.kind, PatKind::Range(..))))
         {
-            let mut min = i128::MAX;
-            let mut max = i128::MIN;
+            let mut min = Num::dummy(i128::MAX);
+            let mut max = Num::dummy(i128::MIN);
+            let mut range_kind = RangeEnd::Included;
             let mut numbers_found = FxHashSet::default();
             let mut ranges_found = Vec::new();
 
             for pat in pats {
                 if let PatKind::Lit(lit) = pat.kind
-                    && let Some(num) = expr_as_i128(lit)
+                    && let Some(num) = Num::new(lit)
                 {
-                    numbers_found.insert(num);
+                    numbers_found.insert(num.val);
 
                     min = min.min(num);
-                    max = max.max(num);
+                    if num.val >= max.val {
+                        max = num;
+                        range_kind = RangeEnd::Included;
+                    }
                 } else if let PatKind::Range(Some(left), Some(right), end) = pat.kind
-                    && let Some(left) = expr_as_i128(left)
-                    && let Some(right) = expr_as_i128(right)
-                    && right >= left
+                    && let Some(left) = Num::new(left)
+                    && let Some(mut right) = Num::new(right)
                 {
+                    if let RangeEnd::Excluded = end {
+                        right.val -= 1;
+                    }
+
                     min = min.min(left);
-                    max = max.max(right);
-                    ranges_found.push(left..=match end {
-                        RangeEnd::Included => right,
-                        RangeEnd::Excluded => right - 1,
-                    });
+                    if right.val > max.val {
+                        max = right;
+                        range_kind = end;
+                    }
+                    ranges_found.push(left.val..=right.val);
                 } else {
                     return;
                 }
             }
 
-            let contains_whole_range = 'contains: {
-                let mut num = min;
-                while num <= max {
-                    if numbers_found.contains(&num) {
-                        num += 1;
-                    }
-                    // Given a list of (potentially overlapping) ranges like:
-                    // 1..=5, 3..=7, 6..=10
-                    // We want to find the range with the highest end that still contains the current number
-                    else if let Some(range) = ranges_found
-                        .iter()
-                        .filter(|range| range.contains(&num))
-                        .max_by_key(|range| range.end())
-                    {
-                        num = range.end() + 1;
-                    } else {
-                        break 'contains false;
-                    }
+            let mut num = min.val;
+            while num <= max.val {
+                if numbers_found.contains(&num) {
+                    num += 1;
+                }
+                // Given a list of (potentially overlapping) ranges like:
+                // 1..=5, 3..=7, 6..=10
+                // We want to find the range with the highest end that still contains the current number
+                else if let Some(range) = ranges_found
+                    .iter()
+                    .filter(|range| range.contains(&num))
+                    .max_by_key(|range| range.end())
+                {
+                    num = range.end() + 1;
+                } else {
+                    return;
                 }
-                break 'contains true;
-            };
-
-            if contains_whole_range {
-                span_lint_and_sugg(
-                    cx,
-                    MANUAL_RANGE_PATTERNS,
-                    pat.span,
-                    "this OR pattern can be rewritten using a range",
-                    "try",
-                    format!("{min}..={max}"),
-                    Applicability::MachineApplicable,
-                );
             }
+
+            span_lint_and_then(
+                cx,
+                MANUAL_RANGE_PATTERNS,
+                pat.span,
+                "this OR pattern can be rewritten using a range",
+                |diag| {
+                    if let Some(min) = snippet_opt(cx, min.span)
+                        && let Some(max) = snippet_opt(cx, max.span)
+                    {
+                        diag.span_suggestion(
+                            pat.span,
+                            "try",
+                            format!("{min}{range_kind}{max}"),
+                            Applicability::MachineApplicable,
+                        );
+                    }
+                },
+            );
         }
     }
 }