diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs index 300b9aaf10060..29d37af30fc49 100644 --- a/src/librustc/lint/builtin.rs +++ b/src/librustc/lint/builtin.rs @@ -26,6 +26,9 @@ //! a `pub fn new()`. use self::MethodContext::*; + +use fmt_macros::{Parser, Piece, Position}; + use metadata::csearch; use middle::def::*; use middle::subst::Substs; @@ -1921,3 +1924,63 @@ impl LintPass for UnstableFeatures { } } } + +/// Checks usage of `#[on_unimplemented]` +#[derive(Copy)] +pub struct BadOnUnimplemented; + +declare_lint!(BAD_ON_UNIMPLEMENTED, Deny, + "Checks usage of `#[on_unimplemented]`"); + +impl LintPass for BadOnUnimplemented { + fn get_lints(&self) -> LintArray { + lint_array!(BAD_ON_UNIMPLEMENTED) + } + fn check_item(&mut self, ctx: &Context, item: &ast::Item) { + match item.node { + ast::ItemTrait(_, ref generics, _, _) => { + if let Some(ref attr) = item.attrs.iter().find(|&: a| { + a.check_name("on_unimplemented") + }) { + if let Some(ref istring) = attr.value_str() { + let mut parser = Parser::new(istring.get()); + let types = generics.ty_params.as_slice(); + for token in parser { + match token { + Piece::String(_) => (), // Normal string, no need to check it + Piece::NextArgument(a) => match a.position { + // `{Self}` is allowed + Position::ArgumentNamed(s) if s == "Self" => (), + // So is `{A}` if A is a type parameter + Position::ArgumentNamed(s) => match types.iter().find(|t| { + t.ident.as_str() == s + }) { + Some(_) => (), + None => { + ctx.span_lint(BAD_ON_UNIMPLEMENTED, attr.span, + format!("there is no type parameter \ + {} on trait {}", + s, item.ident.as_str()) + .as_slice()); + } + }, + // `{:1}` and `{}` are not to be used + Position::ArgumentIs(_) | Position::ArgumentNext => { + ctx.span_lint(BAD_ON_UNIMPLEMENTED, attr.span, + "only named substitution \ + parameters are allowed"); + } + } + } + } + } else { + ctx.span_lint(BAD_ON_UNIMPLEMENTED, attr.span, + "this attribute must have a value, \ + eg `#[on_unimplemented = \"foo\"]`") + } + } + }, + _ => () // Not a trait def, move along + } + } +} \ No newline at end of file diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs index 95e1e8d44bfc5..b50c505a3aced 100644 --- a/src/librustc/lint/context.rs +++ b/src/librustc/lint/context.rs @@ -211,6 +211,7 @@ impl LintStore { UnusedAllocation, MissingCopyImplementations, UnstableFeatures, + BadOnUnimplemented, ); add_builtin_with_new!(sess, diff --git a/src/test/compile-fail/on-unimplemented-bad-anno.rs b/src/test/compile-fail/on-unimplemented-bad-anno.rs new file mode 100644 index 0000000000000..7ca228a69b8b1 --- /dev/null +++ b/src/test/compile-fail/on-unimplemented-bad-anno.rs @@ -0,0 +1,32 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +// ignore-tidy-linelength + +#[allow(unused)] + +#[on_unimplemented = "test error `{Self}` with `{Bar}` `{Baz}` `{Quux}`"] +trait Foo{} + +#[on_unimplemented="a collection of type `{Self}` cannot be built from an iterator over elements of type `{A}`"] +trait MyFromIterator { + /// Build a container with elements from an external iterator. + fn my_from_iter>(iterator: T) -> Self; +} + +#[on_unimplemented] //~ ERROR this attribute must have a value +trait BadAnnotation1 {} + +#[on_unimplemented = "Unimplemented trait error on `{Self}` with params `<{A},{B},{C}>`"] +//~^ ERROR there is no type parameter C on trait BadAnnotation2 +trait BadAnnotation2 {} + + +pub fn main() { +}