From 44d27ba28df30f80d039f0486cac46d7fb265fa3 Mon Sep 17 00:00:00 2001 From: "Felix S. Klock II" Date: Fri, 12 Jul 2019 15:32:12 +0200 Subject: [PATCH] Change `indirect_structural_match` lint to allow-by-default. This is a way to address the regression aspect of rust-lang/rust#62614 in the short term without actually fixing the bug. (My thinking is that the bug that this lint detects has gone undetected for this long, it can wait a bit longer until I or someone else has a chance to put in a proper fix that accounts for rust-lang/rust#62614.) --- src/librustc/lint/builtin.rs | 4 +- .../allow-use-behind-cousin-variant.rs | 59 +++++++++++++++++++ 2 files changed, 62 insertions(+), 1 deletion(-) create mode 100644 src/test/ui/rfc1445/allow-use-behind-cousin-variant.rs diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs index 9b4b97202d96d..d1cae76de60a1 100644 --- a/src/librustc/lint/builtin.rs +++ b/src/librustc/lint/builtin.rs @@ -350,7 +350,8 @@ declare_lint! { declare_lint! { pub INDIRECT_STRUCTURAL_MATCH, - Warn, + // defaulting to allow until rust-lang/rust#62614 is fixed. + Allow, "pattern with const indirectly referencing non-`#[structural_match]` type" } @@ -451,6 +452,7 @@ declare_lint_pass! { AMBIGUOUS_ASSOCIATED_ITEMS, NESTED_IMPL_TRAIT, MUTABLE_BORROW_RESERVATION_CONFLICT, + INDIRECT_STRUCTURAL_MATCH, ] } diff --git a/src/test/ui/rfc1445/allow-use-behind-cousin-variant.rs b/src/test/ui/rfc1445/allow-use-behind-cousin-variant.rs new file mode 100644 index 0000000000000..dca8aaef1500d --- /dev/null +++ b/src/test/ui/rfc1445/allow-use-behind-cousin-variant.rs @@ -0,0 +1,59 @@ +// rust-lang/rust#62614: we want to allow matching on constants of types that +// have non-structural-match variants, *if* the constant itself does not use +// any such variant. + +// NOTE: for now, deliberately leaving the lint `indirect_structural_match` set +// to its default, so that we will not issue a diangostic even if +// rust-lang/rust#62614 remains an open issue. + +// run-pass + +struct Sum(u32, u32); + +impl PartialEq for Sum { + fn eq(&self, other: &Self) -> bool { self.0 + self.1 == other.0 + other.1 } +} + +impl Eq for Sum { } + +#[derive(PartialEq, Eq)] +enum Eek { + TheConst, + UnusedByTheConst(Sum) +} + +const THE_CONST: Eek = Eek::TheConst; +const SUM_THREE: Eek = Eek::UnusedByTheConst(Sum(3,0)); + +const EEK_ZERO: &[Eek] = &[]; +const EEK_ONE: &[Eek] = &[THE_CONST]; + +pub fn main() { + match Eek::UnusedByTheConst(Sum(1,2)) { + ref sum if sum == &SUM_THREE => { println!("Hello 0"); } + _ => { println!("Gbye"); } + } + + match Eek::TheConst { + THE_CONST => { println!("Hello 1"); } + _ => { println!("Gbye"); } + } + + + match & &Eek::TheConst { + & & THE_CONST => { println!("Hello 2"); } + _ => { println!("Gbye"); } + } + + match & & &[][..] { + & & EEK_ZERO => { println!("Hello 3"); } + & & EEK_ONE => { println!("Gbye"); } + _ => { println!("Gbye"); } + } + + match & & &[Eek::TheConst][..] { + & & EEK_ZERO => { println!("Gby"); } + & & EEK_ONE => { println!("Hello 4"); } + _ => { println!("Gbye"); } + } +}