Fix #3112

clippy_lints/src/eval_order_dependence.rs

@@ -109,7 +109,9 @@ impl<'a, 'tcx> DivergenceVisitor<'a, 'tcx> {
                 self.visit_expr(e);
                 for arm in arms {
                     if let Some(ref guard) = arm.guard {
-                        self.visit_expr(guard);
+                        match guard {
+                            Guard::If(if_expr) => self.visit_expr(if_expr),
+                        }
                     }
                     // make sure top level arm expressions aren't linted
                     self.maybe_walk_expr(&*arm.body);

clippy_lints/src/shadow.rs

@@ -339,7 +339,9 @@ fn check_expr<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, bindings:
                     check_pat(cx, pat, Some(&**init), pat.span, bindings);
                     // This is ugly, but needed to get the right type
                     if let Some(ref guard) = arm.guard {
-                        check_expr(cx, guard, bindings);
+                        match guard {
+                            Guard::If(if_expr) => check_expr(cx, if_expr, bindings),
+                        }
                     }
                     check_expr(cx, &arm.body, bindings);
                     bindings.truncate(len);

clippy_lints/src/utils/author.rs

@@ -345,9 +345,15 @@ impl<'tcx> Visitor<'tcx> for PrintVisitor {
                     self.visit_expr(&arm.body);
                     if let Some(ref guard) = arm.guard {
                         let guard_pat = self.next("guard");
-                        println!("    if let Some(ref {}) = {}[{}].guard", guard_pat, arms_pat, i);
-                        self.current = guard_pat;
-                        self.visit_expr(guard);
+                        println!("    if let Some(ref {}) = {}[{}].guard;", guard_pat, arms_pat, i);
+                        match guard {
+                            hir::Guard::If(ref if_expr) => {
+                                let if_expr_pat = self.next("expr");
+                                println!("    if let Guard::If(ref {}) = {};", if_expr_pat, guard_pat);
+                                self.current = if_expr_pat;
+                                self.visit_expr(if_expr);
+                            }
+                        }
                     }
                     println!("    if {}[{}].pats.len() == {};", arms_pat, i, arm.pats.len());
                     for (j, pat) in arm.pats.iter().enumerate() {

clippy_lints/src/utils/hir_utils.rs

@@ -113,7 +113,7 @@ impl<'a, 'tcx: 'a> SpanlessEq<'a, 'tcx> {
             },
             (&ExprKind::Match(ref le, ref la, ref ls), &ExprKind::Match(ref re, ref ra, ref rs)) => {
                 ls == rs && self.eq_expr(le, re) && over(la, ra, |l, r| {
-                    self.eq_expr(&l.body, &r.body) && both(&l.guard, &r.guard, |l, r| self.eq_expr(l, r))
+                    self.eq_expr(&l.body, &r.body) && both(&l.guard, &r.guard, |l, r| self.eq_guard(l, r))
                         && over(&l.pats, &r.pats, |l, r| self.eq_pat(l, r))
                 })
             },
@@ -152,6 +152,12 @@ impl<'a, 'tcx: 'a> SpanlessEq<'a, 'tcx> {
         left.ident.name == right.ident.name && self.eq_expr(&left.expr, &right.expr)
     }
 
+    fn eq_guard(&mut self, left: &Guard, right: &Guard) -> bool {
+        match (left, right) {
+            (Guard::If(l), Guard::If(r)) => self.eq_expr(l, r),
+        }
+    }
+
     fn eq_generic_arg(&mut self, left: &GenericArg, right: &GenericArg) -> bool {
         match (left, right) {
             (GenericArg::Lifetime(l_lt), GenericArg::Lifetime(r_lt)) => self.eq_lifetime(l_lt, r_lt),
@@ -497,7 +503,7 @@ impl<'a, 'tcx: 'a> SpanlessHash<'a, 'tcx> {
                 for arm in arms {
                     // TODO: arm.pat?
                     if let Some(ref e) = arm.guard {
-                        self.hash_expr(e);
+                        self.hash_guard(e);
                     }
                     self.hash_expr(&arm.body);
                 }
@@ -637,4 +643,14 @@ impl<'a, 'tcx: 'a> SpanlessHash<'a, 'tcx> {
             },
         }
     }
+
+    pub fn hash_guard(&mut self, g: &Guard) {
+        match g {
+            Guard::If(ref expr) => {
+                let c: fn(_) -> _ = Guard::If;
+                c.hash(&mut self.s);
+                self.hash_expr(expr);
+            }
+        }
+    }
 }

clippy_lints/src/utils/inspector.rs

@@ -113,7 +113,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
         }
         if let Some(ref guard) = arm.guard {
             println!("guard:");
-            print_expr(cx, guard, 1);
+            print_guard(cx, guard, 1);
         }
         println!("body:");
         print_expr(cx, &arm.body, 1);
@@ -515,3 +515,14 @@ fn print_pat(cx: &LateContext<'_, '_>, pat: &hir::Pat, indent: usize) {
         },
     }
 }
+
+fn print_guard(cx: &LateContext<'_, '_>, guard: &hir::Guard, indent: usize) {
+    let ind = "  ".repeat(indent);
+    println!("{}+", ind);
+    match guard {
+        hir::Guard::If(expr) => {
+            println!("{}If", ind);
+            print_expr(cx, expr, indent + 1);
+        }
+    }
+}