diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 4e5fc47..414579a 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -27,7 +27,7 @@
         .expect("RUST_MIN_STACK env var should be set since some tests require it.");
     let min_stack_value: usize = min_stack_value.parse()
         .expect("RUST_MIN_STACK env var should be set since some tests require it.");
-    assert!(min_stack_value >= 16000000);
+    assert!(min_stack_value >= 16_000_000);
 }
 
 /// Read the `ABORT_AFTER_FAILURE` environment variable, and parse it.
diff --git a/tests/test_grouping.rs b/tests/test_grouping.rs
index fa8b6eb..8c3733a 100644
--- a/tests/test_grouping.rs
+++ b/tests/test_grouping.rs
@@ -82,7 +82,7 @@
 
     assert_eq!(raw.to_string(), "1i32 +  2i32 +  3i32 * 4i32");
 
-    assert_eq!(common::parse::syn::<Expr>(raw.into()), expr(ExprBinary {
+    assert_eq!(common::parse::syn::<Expr>(raw), expr(ExprBinary {
         left: Box::new(expr(ExprBinary {
             left: Box::new(lit(Literal::i32(1))),
             op: BinOp::Add(<Token![+]>::default()),
diff --git a/tests/test_meta_item.rs b/tests/test_meta_item.rs
index 26502c9..ec4d082 100644
--- a/tests/test_meta_item.rs
+++ b/tests/test_meta_item.rs
@@ -102,7 +102,7 @@
             assert!(rest.eof());
             e
         }
-        Err(_) => panic!("failed to parse"),
+        Err(err) => panic!(err),
     };
     assert_eq!(expected.into(), attr.meta_item().unwrap());
 }
diff --git a/tests/test_precedence.rs b/tests/test_precedence.rs
index 8ef0a79..c5673a6 100644
--- a/tests/test_precedence.rs
+++ b/tests/test_precedence.rs
@@ -182,7 +182,7 @@
 }
 
 fn libsyntax_parse_and_rewrite(input: &str) -> Option<P<ast::Expr>> {
-    parse::libsyntax_expr(input).and_then(|e| libsyntax_brackets(e))
+    parse::libsyntax_expr(input).and_then(libsyntax_brackets)
 }
 
 /// Wrap every expression which is not already wrapped in parens with parens, to
diff --git a/tests/test_round_trip.rs b/tests/test_round_trip.rs
index 60b0c2b..243a50b 100644
--- a/tests/test_round_trip.rs
+++ b/tests/test_round_trip.rs
@@ -101,7 +101,7 @@
             if before == after {
                 errorf!("=== {}: pass in {}ms\n",
                         path.display(),
-                        elapsed.as_secs() * 1000 + elapsed.subsec_nanos() as u64 / 1_000_000);
+                        elapsed.as_secs() * 1000 + u64::from(elapsed.subsec_nanos()) / 1_000_000);
                 true
             } else {
                 errorf!("=== {}: FAIL\nbefore: {}\nafter: {}\n",