Merge branch 'master' into issue-4078

Author: EthanTheMaster

.github/PULL_REQUEST_TEMPLATE renamed to .github/PULL_REQUEST_TEMPLATE.md

@@ -1,4 +1,3 @@
-<!--
 Thank you for making Clippy better!
 
 We're collecting our changelog from pull request descriptions.
@@ -25,6 +24,8 @@ checked during review or continuous integration.
 Note that you can skip the above if you are just opening a WIP PR in
 order to get feedback.
 
-Delete this line and everything above before opening your PR -->
+Delete this line and everything above before opening your PR.
+
+---
 
 changelog: none

CHANGELOG.md

@@ -976,6 +976,7 @@ Released 2018-09-13
 [`diverging_sub_expression`]: https://rust-lang.github.io/rust-clippy/master/index.html#diverging_sub_expression
 [`doc_markdown`]: https://rust-lang.github.io/rust-clippy/master/index.html#doc_markdown
 [`double_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_comparisons
+[`double_must_use`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_must_use
 [`double_neg`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_neg
 [`double_parens`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_parens
 [`drop_bounds`]: https://rust-lang.github.io/rust-clippy/master/index.html#drop_bounds
@@ -1095,6 +1096,8 @@ Released 2018-09-13
 [`modulo_one`]: https://rust-lang.github.io/rust-clippy/master/index.html#modulo_one
 [`multiple_crate_versions`]: https://rust-lang.github.io/rust-clippy/master/index.html#multiple_crate_versions
 [`multiple_inherent_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#multiple_inherent_impl
+[`must_use_candidate`]: https://rust-lang.github.io/rust-clippy/master/index.html#must_use_candidate
+[`must_use_unit`]: https://rust-lang.github.io/rust-clippy/master/index.html#must_use_unit
 [`mut_from_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#mut_from_ref
 [`mut_mut`]: https://rust-lang.github.io/rust-clippy/master/index.html#mut_mut
 [`mut_range_bound`]: https://rust-lang.github.io/rust-clippy/master/index.html#mut_range_bound

CONTRIBUTING.md

@@ -147,7 +147,7 @@ You can use [rustup-toolchain-install-master][rtim] to do that:
 
 ```bash
 cargo install rustup-toolchain-install-master
-rustup-toolchain-install-master -n master --force
+rustup-toolchain-install-master --force -n master
 rustup override set master
 cargo test
 ```

Cargo.toml

@@ -46,7 +46,7 @@ rustc_tools_util = { version = "0.2.0", path = "rustc_tools_util"}
 
 [dev-dependencies]
 cargo_metadata = "0.8.0"
-compiletest_rs = { version = "0.3.23", features = ["tmp"] }
+compiletest_rs = { version = "0.3.24", features = ["tmp"] }
 lazy_static = "1.0"
 clippy-mini-macro-test = { version = "0.2", path = "mini-macro" }
 serde = { version = "1.0", features = ["derive"] }

README.md

@@ -6,7 +6,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 322 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are 324 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

appveyor.yml

@@ -17,11 +17,9 @@ install:
     - curl -sSf -o rustup-init.exe https://win.rustup.rs/
     - rustup-init.exe -y --default-host %TARGET% --default-toolchain nightly
     - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
-    - git ls-remote https://github.com/rust-lang/rust.git master | awk '{print $1}' >rustc-hash.txt
-    - set /p RUSTC_HASH=<rustc-hash.txt
     - del rust-toolchain
-    - cargo install rustup-toolchain-install-master --debug || echo "rustup-toolchain-install-master already installed"
-    - rustup-toolchain-install-master %RUSTC_HASH% -f -n master
+    - cargo install --git https://github.com/kennytm/rustup-toolchain-install-master --debug || echo "rustup-toolchain-install-master already installed"
+    - rustup-toolchain-install-master -f -n master
     - rustup component add rustfmt --toolchain nightly & exit 0 # Format test handles missing rustfmt
     - rustup default master
     - set PATH=%PATH%;C:\Users\appveyor\.rustup\toolchains\master\bin

clippy_dev/src/lib.rs

@@ -42,6 +42,7 @@ pub struct Lint {
 }
 
 impl Lint {
+    #[must_use]
     pub fn new(name: &str, group: &str, desc: &str, deprecation: Option<&str>, module: &str) -> Self {
         Self {
             name: name.to_lowercase(),
@@ -58,19 +59,22 @@ impl Lint {
     }
 
     /// Returns the lints in a `HashMap`, grouped by the different lint groups
+    #[must_use]
     pub fn by_lint_group(lints: &[Self]) -> HashMap<String, Vec<Self>> {
         lints
             .iter()
             .map(|lint| (lint.group.to_string(), lint.clone()))
             .into_group_map()
     }
 
+    #[must_use]
     pub fn is_internal(&self) -> bool {
         self.group.starts_with("internal")
     }
 }
 
 /// Generates the Vec items for `register_lint_group` calls in `clippy_lints/src/lib.rs`.
+#[must_use]
 pub fn gen_lint_group_list(lints: Vec<Lint>) -> Vec<String> {
     lints
         .into_iter()
@@ -86,6 +90,7 @@ pub fn gen_lint_group_list(lints: Vec<Lint>) -> Vec<String> {
 }
 
 /// Generates the `pub mod module_name` list in `clippy_lints/src/lib.rs`.
+#[must_use]
 pub fn gen_modules_list(lints: Vec<Lint>) -> Vec<String> {
     lints
         .into_iter()
@@ -103,6 +108,7 @@ pub fn gen_modules_list(lints: Vec<Lint>) -> Vec<String> {
 }
 
 /// Generates the list of lint links at the bottom of the README
+#[must_use]
 pub fn gen_changelog_lint_list(lints: Vec<Lint>) -> Vec<String> {
     let mut lint_list_sorted: Vec<Lint> = lints;
     lint_list_sorted.sort_by_key(|l| l.name.clone());
@@ -119,6 +125,7 @@ pub fn gen_changelog_lint_list(lints: Vec<Lint>) -> Vec<String> {
 }
 
 /// Generates the `register_removed` code in `./clippy_lints/src/lib.rs`.
+#[must_use]
 pub fn gen_deprecated(lints: &[Lint]) -> Vec<String> {
     lints
         .iter()

clippy_dev/src/stderr_length_check.rs

@@ -42,6 +42,7 @@ fn stderr_files() -> impl Iterator<Item = walkdir::DirEntry> {
         .filter(|f| f.path().extension() == Some(OsStr::new("stderr")))
 }
 
+#[must_use]
 fn count_linenumbers(filepath: &str) -> usize {
     if let Ok(mut file) = File::open(filepath) {
         let mut content = String::new();

clippy_lints/src/approx_const.rs

@@ -93,6 +93,7 @@ fn check_known_consts(cx: &LateContext<'_, '_>, e: &Expr, s: symbol::Symbol, mod
 /// Returns `false` if the number of significant figures in `value` are
 /// less than `min_digits`; otherwise, returns true if `value` is equal
 /// to `constant`, rounded to the number of digits present in `value`.
+#[must_use]
 fn is_approx_const(constant: f64, value: &str, min_digits: usize) -> bool {
     if value.len() <= min_digits {
         false

clippy_lints/src/assertions_on_constants.rs

@@ -1,6 +1,6 @@
 use crate::consts::{constant, Constant};
 use crate::utils::paths;
-use crate::utils::{is_direct_expn_of, is_expn_of, match_def_path, snippet_opt, span_help_and_lint};
+use crate::utils::{is_direct_expn_of, is_expn_of, match_function_call, snippet_opt, span_help_and_lint};
 use if_chain::if_chain;
 use rustc::hir::*;
 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
@@ -145,23 +145,3 @@ fn match_assert_with_message<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx E
     }
     None
 }
-
-/// Matches a function call with the given path and returns the arguments.
-///
-/// Usage:
-///
-/// ```rust,ignore
-/// if let Some(args) = match_function_call(cx, begin_panic_call, &paths::BEGIN_PANIC);
-/// ```
-fn match_function_call<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, path: &[&str]) -> Option<&'a [Expr]> {
-    if_chain! {
-        if let ExprKind::Call(ref fun, ref args) = expr.kind;
-        if let ExprKind::Path(ref qpath) = fun.kind;
-        if let Some(fun_def_id) = cx.tables.qpath_res(qpath, fun.hir_id).opt_def_id();
-        if match_def_path(cx, fun_def_id, path);
-        then {
-            return Some(&args)
-        }
-    };
-    None
-}