From 6c50ee5abc1f41aaf587f74cc317819ff8eca7d8 Mon Sep 17 00:00:00 2001 From: "Zack M. Davis" Date: Sat, 21 Jul 2018 17:55:34 -0700 Subject: [PATCH] dead-code lint: say "constructed" for structs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a sequel to November 2017's #46103 / 1a9dc2e9. It had been reported (more than once—at least #19140, #44083, and #44565) that the "never used" language was confusing for enum variants that were "used" as match patterns, so the wording was changed to say never "constructed" specifically for enum variants. More recently, the same issue was raised for structs (#52325). It seems consistent to say "constructed" here, too, for the same reasons. We considered using more specific word "called" for unused functions and methods (while we declined to do this in #46103, the rationale given in the commit message doesn't actually make sense), but it turns out that Cargo's test suite expects the "never used" message, and maybe we don't care enough even to make a Cargo PR over such a petty and subjective wording change. This resolves #52325. --- src/librustc/middle/dead.rs | 6 +++++- src/test/compile-fail/lint-dead-code-1.rs | 4 ++-- src/test/compile-fail/lint-dead-code-3.rs | 2 +- src/test/ui/span/macro-span-replacement.rs | 2 +- src/test/ui/span/macro-span-replacement.stderr | 4 ++-- src/test/ui/span/unused-warning-point-at-signature.rs | 2 +- src/test/ui/span/unused-warning-point-at-signature.stderr | 4 ++-- 7 files changed, 14 insertions(+), 10 deletions(-) diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs index e4fc1b09fcebc..0f889549b58e3 100644 --- a/src/librustc/middle/dead.rs +++ b/src/librustc/middle/dead.rs @@ -554,12 +554,16 @@ impl<'a, 'tcx> Visitor<'tcx> for DeadVisitor<'a, 'tcx> { hir::ItemKind::Impl(..) => self.tcx.sess.codemap().def_span(item.span), _ => item.span, }; + let participle = match item.node { + hir::ItemKind::Struct(..) => "constructed", // Issue #52325 + _ => "used" + }; self.warn_dead_code( item.id, span, item.name, item.node.descriptive_variant(), - "used", + participle, ); } else { // Only continue if we didn't warn diff --git a/src/test/compile-fail/lint-dead-code-1.rs b/src/test/compile-fail/lint-dead-code-1.rs index d6ca5e6b1d969..2fe72365bab1c 100644 --- a/src/test/compile-fail/lint-dead-code-1.rs +++ b/src/test/compile-fail/lint-dead-code-1.rs @@ -19,7 +19,7 @@ pub use foo2::Bar2; mod foo { - pub struct Bar; //~ ERROR: struct is never used + pub struct Bar; //~ ERROR: struct is never constructed } mod foo2 { @@ -42,7 +42,7 @@ const CONST_USED_IN_ENUM_DISCRIMINANT: isize = 11; pub type typ = *const UsedStruct4; pub struct PubStruct; -struct PrivStruct; //~ ERROR: struct is never used +struct PrivStruct; //~ ERROR: struct is never constructed struct UsedStruct1 { #[allow(dead_code)] x: isize diff --git a/src/test/compile-fail/lint-dead-code-3.rs b/src/test/compile-fail/lint-dead-code-3.rs index f680e39544933..112d363095253 100644 --- a/src/test/compile-fail/lint-dead-code-3.rs +++ b/src/test/compile-fail/lint-dead-code-3.rs @@ -20,7 +20,7 @@ extern { pub fn extern_foo(); } -struct Foo; //~ ERROR: struct is never used +struct Foo; //~ ERROR: struct is never constructed impl Foo { fn foo(&self) { //~ ERROR: method is never used bar() diff --git a/src/test/ui/span/macro-span-replacement.rs b/src/test/ui/span/macro-span-replacement.rs index 4fe35042300e7..7374f15746851 100644 --- a/src/test/ui/span/macro-span-replacement.rs +++ b/src/test/ui/span/macro-span-replacement.rs @@ -14,7 +14,7 @@ macro_rules! m { ($a:tt $b:tt) => { - $b $a; //~ WARN struct is never used + $b $a; //~ WARN struct is never constructed } } diff --git a/src/test/ui/span/macro-span-replacement.stderr b/src/test/ui/span/macro-span-replacement.stderr index bb59fa206df1d..b12ca86d3c929 100644 --- a/src/test/ui/span/macro-span-replacement.stderr +++ b/src/test/ui/span/macro-span-replacement.stderr @@ -1,7 +1,7 @@ -warning: struct is never used: `S` +warning: struct is never constructed: `S` --> $DIR/macro-span-replacement.rs:17:14 | -LL | $b $a; //~ WARN struct is never used +LL | $b $a; //~ WARN struct is never constructed | ^ ... LL | m!(S struct); diff --git a/src/test/ui/span/unused-warning-point-at-signature.rs b/src/test/ui/span/unused-warning-point-at-signature.rs index 6a7071d49aed6..c074f03db469c 100644 --- a/src/test/ui/span/unused-warning-point-at-signature.rs +++ b/src/test/ui/span/unused-warning-point-at-signature.rs @@ -19,7 +19,7 @@ enum Enum { //~ WARN enum is never used D, } -struct Struct { //~ WARN struct is never used +struct Struct { //~ WARN struct is never constructed a: usize, b: usize, c: usize, diff --git a/src/test/ui/span/unused-warning-point-at-signature.stderr b/src/test/ui/span/unused-warning-point-at-signature.stderr index de234344d8409..8344853d6def5 100644 --- a/src/test/ui/span/unused-warning-point-at-signature.stderr +++ b/src/test/ui/span/unused-warning-point-at-signature.stderr @@ -11,10 +11,10 @@ LL | #![warn(unused)] | ^^^^^^ = note: #[warn(dead_code)] implied by #[warn(unused)] -warning: struct is never used: `Struct` +warning: struct is never constructed: `Struct` --> $DIR/unused-warning-point-at-signature.rs:22:1 | -LL | struct Struct { //~ WARN struct is never used +LL | struct Struct { //~ WARN struct is never constructed | ^^^^^^^^^^^^^ warning: function is never used: `func`