diff --git a/clippy_lints/src/assertions_on_constants.rs b/clippy_lints/src/assertions_on_constants.rs
index 0f0c0dbc1..32ca1cc1b 100644
--- a/clippy_lints/src/assertions_on_constants.rs
+++ b/clippy_lints/src/assertions_on_constants.rs
@@ -1,11 +1,9 @@
-use if_chain::if_chain;
 use rustc::hir::{Expr, ExprKind};
 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use rustc::{declare_lint_pass, declare_tool_lint};
-use syntax_pos::Span;
 
 use crate::consts::{constant, Constant};
-use crate::utils::{in_macro_or_desugar, is_direct_expn_of, span_help_and_lint};
+use crate::utils::{in_macro_or_desugar, is_direct_expn_of, is_expn_of, span_help_and_lint};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
@@ -33,42 +31,39 @@ declare_lint_pass!(AssertionsOnConstants => [ASSERTIONS_ON_CONSTANTS]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
-        let mut is_debug_assert = false;
-        let debug_assert_not_in_macro_or_desugar = |span: Span| {
-            is_debug_assert = true;
-            // Check that `debug_assert!` itself is not inside a macro
-            !in_macro_or_desugar(span)
-        };
-        if_chain! {
-            if let Some(assert_span) = is_direct_expn_of(e.span, "assert");
-            if !in_macro_or_desugar(assert_span)
-                || is_direct_expn_of(assert_span, "debug_assert")
-                    .map_or(false, debug_assert_not_in_macro_or_desugar);
-            if let ExprKind::Unary(_, ref lit) = e.node;
-            if let Some(bool_const) = constant(cx, cx.tables, lit);
-            then {
-                match bool_const.0 {
-                    Constant::Bool(true) => {
+        let lint_assert_cb = |is_debug_assert: bool| {
+            if let ExprKind::Unary(_, ref lit) = e.node {
+                if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, lit) {
+                    if is_true {
                         span_help_and_lint(
                             cx,
                             ASSERTIONS_ON_CONSTANTS,
                             e.span,
                             "`assert!(true)` will be optimized out by the compiler",
-                            "remove it"
+                            "remove it",
                         );
-                    },
-                    Constant::Bool(false) if !is_debug_assert => {
+                    } else if !is_debug_assert {
                         span_help_and_lint(
                             cx,
                             ASSERTIONS_ON_CONSTANTS,
                             e.span,
                             "`assert!(false)` should probably be replaced",
-                            "use `panic!()` or `unreachable!()`"
+                            "use `panic!()` or `unreachable!()`",
                         );
-                    },
-                    _ => (),
+                    }
                 }
             }
+        };
+        if let Some(debug_assert_span) = is_expn_of(e.span, "debug_assert") {
+            if in_macro_or_desugar(debug_assert_span) {
+                return;
+            }
+            lint_assert_cb(true);
+        } else if let Some(assert_span) = is_direct_expn_of(e.span, "assert") {
+            if in_macro_or_desugar(assert_span) {
+                return;
+            }
+            lint_assert_cb(false);
         }
     }
 }
diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 64239bb4d..01989625b 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -298,16 +298,16 @@ fn bindings<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, pat: &Pat) -> FxHashMap<LocalI
                     bindings_impl(cx, as_pat, map);
                 }
             },
+            PatKind::Or(ref fields) | PatKind::Tuple(ref fields, _) => {
+                for pat in fields {
+                    bindings_impl(cx, pat, map);
+                }
+            },
             PatKind::Struct(_, ref fields, _) => {
                 for pat in fields {
                     bindings_impl(cx, &pat.pat, map);
                 }
             },
-            PatKind::Tuple(ref fields, _) => {
-                for pat in fields {
-                    bindings_impl(cx, pat, map);
-                }
-            },
             PatKind::Slice(ref lhs, ref mid, ref rhs) => {
                 for pat in lhs {
                     bindings_impl(cx, pat, map);
diff --git a/clippy_lints/src/utils/author.rs b/clippy_lints/src/utils/author.rs
index 6d9eddac8..4cf52ddac 100644
--- a/clippy_lints/src/utils/author.rs
+++ b/clippy_lints/src/utils/author.rs
@@ -549,6 +549,12 @@ impl<'tcx> Visitor<'tcx> for PrintVisitor {
                 println!("    if {}.len() == {};", fields_pat, fields.len());
                 println!("    // unimplemented: field checks");
             },
+            PatKind::Or(ref fields) => {
+                let fields_pat = self.next("fields");
+                println!("Or(ref {}) = {};", fields_pat, current);
+                println!("    if {}.len() == {};", fields_pat, fields.len());
+                println!("    // unimplemented: field checks");
+            },
             PatKind::TupleStruct(ref path, ref fields, skip_pos) => {
                 let path_pat = self.next("path");
                 let fields_pat = self.next("fields");
diff --git a/clippy_lints/src/utils/inspector.rs b/clippy_lints/src/utils/inspector.rs
index 309b5165c..b48ef7d29 100644
--- a/clippy_lints/src/utils/inspector.rs
+++ b/clippy_lints/src/utils/inspector.rs
@@ -410,6 +410,12 @@ fn print_pat(cx: &LateContext<'_, '_>, pat: &hir::Pat, indent: usize) {
                 print_pat(cx, inner, indent + 1);
             }
         },
+        hir::PatKind::Or(ref fields) => {
+            println!("{}Or", ind);
+            for field in fields {
+                print_pat(cx, field, indent + 1);
+            }
+        },
         hir::PatKind::Struct(ref path, ref fields, ignore) => {
             println!("{}Struct", ind);
             println!(
diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs
index a25f25041..020068d46 100644
--- a/clippy_lints/src/utils/mod.rs
+++ b/clippy_lints/src/utils/mod.rs
@@ -791,7 +791,7 @@ pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
         PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
         PatKind::Lit(..) | PatKind::Range(..) => true,
         PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
-        PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
+        PatKind::Or(ref pats) | PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
         PatKind::Struct(ref qpath, ref fields, _) => {
             if is_enum_variant(cx, qpath, pat.hir_id) {
                 true