diff --git a/crates/cargo-test-macro/src/lib.rs b/crates/cargo-test-macro/src/lib.rs
index b16915762a4..dae129ade66 100644
--- a/crates/cargo-test-macro/src/lib.rs
+++ b/crates/cargo-test-macro/src/lib.rs
@@ -52,7 +52,7 @@ pub fn cargo_test(attr: TokenStream, item: TokenStream) -> TokenStream {
         ))));
     }
 
-    return ret;
+    ret
 }
 
 fn contains_ident(t: &TokenStream, ident: &str) -> bool {
diff --git a/crates/cargo-test-support/src/lib.rs b/crates/cargo-test-support/src/lib.rs
index 6b26d0ed00d..52703fba28d 100644
--- a/crates/cargo-test-support/src/lib.rs
+++ b/crates/cargo-test-support/src/lib.rs
@@ -105,6 +105,9 @@ dependency.
 
 */
 
+#![allow(clippy::needless_doctest_main)] // according to @ehuss this lint is fussy
+#![allow(clippy::inefficient_to_string)] // this causes suggestions that result in `(*s).to_string()`
+
 use std::env;
 use std::ffi::OsStr;
 use std::fmt;
@@ -1141,9 +1144,9 @@ impl Execs {
 
         // Do the template replacements on the expected string.
         let matcher = match &self.process_builder {
-            None => matcher.to_string(),
+            None => matcher,
             Some(p) => match p.get_cwd() {
-                None => matcher.to_string(),
+                None => matcher,
                 Some(cwd) => replace_path(&matcher, cwd, "[CWD]"),
             },
         };
diff --git a/crates/resolver-tests/src/lib.rs b/crates/resolver-tests/src/lib.rs
index c77a050758e..f7dbe52c407 100644
--- a/crates/resolver-tests/src/lib.rs
+++ b/crates/resolver-tests/src/lib.rs
@@ -1,3 +1,6 @@
+#![allow(clippy::many_single_char_names)]
+#![allow(clippy::needless_range_loop)] // false positives
+
 use std::cell::RefCell;
 use std::cmp::PartialEq;
 use std::cmp::{max, min};
diff --git a/crates/resolver-tests/tests/resolve.rs b/crates/resolver-tests/tests/resolve.rs
index 2670efd609f..5fcc3a8a4f3 100644
--- a/crates/resolver-tests/tests/resolve.rs
+++ b/crates/resolver-tests/tests/resolve.rs
@@ -234,7 +234,7 @@ fn pub_fail() {
         pkg!(("e", "0.0.6") => [dep_req_kind("a", "<= 0.0.4", Kind::Normal, true),]),
         pkg!(("kB", "0.0.3") => [dep_req("a", ">= 0.0.5"),dep("e"),]),
     ];
-    let reg = registry(input.clone());
+    let reg = registry(input);
     assert!(resolve_and_validated(vec![dep("kB")], &reg, None).is_err());
 }
 
diff --git a/src/bin/cargo/main.rs b/src/bin/cargo/main.rs
index 1b1f1888d25..b9e7abb6857 100644
--- a/src/bin/cargo/main.rs
+++ b/src/bin/cargo/main.rs
@@ -1,5 +1,4 @@
 #![warn(rust_2018_idioms)] // while we're getting used to 2018
-#![allow(clippy::too_many_arguments)] // large project
 #![allow(clippy::redundant_closure)] // there's a false positive
 #![warn(clippy::needless_borrow)]
 #![warn(clippy::redundant_clone)]
diff --git a/src/cargo/core/profiles.rs b/src/cargo/core/profiles.rs
index f184ee3e44a..13b2260f024 100644
--- a/src/cargo/core/profiles.rs
+++ b/src/cargo/core/profiles.rs
@@ -515,7 +515,7 @@ impl ProfileMaker {
             Some(ref toml) => toml,
             None => return Ok(()),
         };
-        let overrides = match toml.package.as_ref().or(toml.overrides.as_ref()) {
+        let overrides = match toml.package.as_ref().or_else(|| toml.overrides.as_ref()) {
             Some(overrides) => overrides,
             None => return Ok(()),
         };
@@ -612,7 +612,7 @@ fn merge_toml_overrides(
             merge_profile(profile, build_override);
         }
     }
-    if let Some(overrides) = toml.package.as_ref().or(toml.overrides.as_ref()) {
+    if let Some(overrides) = toml.package.as_ref().or_else(|| toml.overrides.as_ref()) {
         if !is_member {
             if let Some(all) = overrides.get(&ProfilePackageSpec::All) {
                 merge_profile(profile, all);
diff --git a/src/cargo/core/resolver/encode.rs b/src/cargo/core/resolver/encode.rs
index 04d9ebd38b4..aeea43c84f8 100644
--- a/src/cargo/core/resolver/encode.rs
+++ b/src/cargo/core/resolver/encode.rs
@@ -564,19 +564,20 @@ pub struct EncodeState<'a> {
 
 impl<'a> EncodeState<'a> {
     pub fn new(resolve: &'a Resolve) -> EncodeState<'a> {
-        let mut counts = None;
-        if *resolve.version() == ResolveVersion::V2 {
+        let counts = if *resolve.version() == ResolveVersion::V2 {
             let mut map = HashMap::new();
             for id in resolve.iter() {
                 let slot = map
                     .entry(id.name())
-                    .or_insert(HashMap::new())
+                    .or_insert_with(HashMap::new)
                     .entry(id.version())
                     .or_insert(0);
                 *slot += 1;
             }
-            counts = Some(map);
-        }
+            Some(map)
+        } else {
+            None
+        };
         EncodeState { counts }
     }
 }
diff --git a/src/cargo/lib.rs b/src/cargo/lib.rs
index 3adb0c1e968..0c214c3d38b 100644
--- a/src/cargo/lib.rs
+++ b/src/cargo/lib.rs
@@ -17,6 +17,7 @@
 #![allow(clippy::type_complexity)] // there's an exceptionally complex type
 #![allow(clippy::wrong_self_convention)] // perhaps `Rc` should be special-cased in Clippy?
 #![allow(clippy::write_with_newline)] // too pedantic
+#![allow(clippy::inefficient_to_string)] // this causes suggestions that result in `(*s).to_string()`
 #![warn(clippy::needless_borrow)]
 #![warn(clippy::redundant_clone)]
 // Unit is now interned, and would probably be better as pass-by-copy, but
diff --git a/src/cargo/ops/registry.rs b/src/cargo/ops/registry.rs
index 1d81c04c6c7..4bea42704c6 100644
--- a/src/cargo/ops/registry.rs
+++ b/src/cargo/ops/registry.rs
@@ -371,13 +371,18 @@ fn registry(
         let mut src = RegistrySource::remote(sid, &HashSet::new(), config);
         // Only update the index if the config is not available or `force` is set.
         let cfg = src.config();
-        let cfg = if force_update || cfg.is_err() {
+        let mut updated_cfg = || {
             src.update()
                 .chain_err(|| format!("failed to update {}", sid))?;
-            cfg.or_else(|_| src.config())?
+            src.config()
+        };
+
+        let cfg = if force_update {
+            updated_cfg()?
         } else {
-            cfg.unwrap()
+            cfg.or_else(|_| updated_cfg())?
         };
+
         cfg.and_then(|cfg| cfg.api)
             .ok_or_else(|| format_err!("{} does not support API commands", sid))?
     };
diff --git a/src/cargo/util/config/de.rs b/src/cargo/util/config/de.rs
index 4471727db0c..0824e4629d1 100644
--- a/src/cargo/util/config/de.rs
+++ b/src/cargo/util/config/de.rs
@@ -254,7 +254,7 @@ impl<'de, 'config> de::MapAccess<'de> for ConfigMapAccess<'config> {
                 };
                 let result = seed.deserialize(name.into_deserializer()).map(Some);
                 self.next = Some(key);
-                return result;
+                result
             }
             None => Ok(None),
         }
@@ -273,7 +273,7 @@ impl<'de, 'config> de::MapAccess<'de> for ConfigMapAccess<'config> {
             key: self.de.key.clone(),
         });
         self.de.key.pop();
-        return result;
+        result
     }
 }
 
diff --git a/src/cargo/util/config/key.rs b/src/cargo/util/config/key.rs
index 9fabe9a00fb..42c82bd2769 100644
--- a/src/cargo/util/config/key.rs
+++ b/src/cargo/util/config/key.rs
@@ -46,7 +46,7 @@ impl ConfigKey {
         for part in key.split('.') {
             cfg.push(part);
         }
-        return cfg;
+        cfg
     }
 
     /// Pushes a new sub-key on this `ConfigKey`. This sub-key should be
diff --git a/src/cargo/util/network.rs b/src/cargo/util/network.rs
index 7637c1c2a46..74cb770a093 100644
--- a/src/cargo/util/network.rs
+++ b/src/cargo/util/network.rs
@@ -112,7 +112,7 @@ fn with_retry_repeats_the_call_then_works() {
     let config = Config::default().unwrap();
     *config.shell() = Shell::from_write(Box::new(Vec::new()));
     let result = with_retry(&config, || results.pop().unwrap());
-    assert_eq!(result.unwrap(), ())
+    assert!(result.is_ok())
 }
 
 #[test]
@@ -135,7 +135,7 @@ fn with_retry_finds_nested_spurious_errors() {
     let config = Config::default().unwrap();
     *config.shell() = Shell::from_write(Box::new(Vec::new()));
     let result = with_retry(&config, || results.pop().unwrap());
-    assert_eq!(result.unwrap(), ())
+    assert!(result.is_ok())
 }
 
 #[test]
diff --git a/tests/testsuite/main.rs b/tests/testsuite/main.rs
index 75048c5378a..280fe025653 100644
--- a/tests/testsuite/main.rs
+++ b/tests/testsuite/main.rs
@@ -3,6 +3,8 @@
 #![allow(clippy::blacklisted_name)]
 #![allow(clippy::explicit_iter_loop)]
 #![allow(clippy::redundant_closure)]
+#![allow(clippy::block_in_if_condition_stmt)] // clippy doesn't agree with rustfmt 😂
+#![allow(clippy::inefficient_to_string)] // this causes suggestions that result in `(*s).to_string()`
 #![warn(clippy::needless_borrow)]
 #![warn(clippy::redundant_clone)]