Auto merge of #40346 - jseyfried:path_and_tokenstream_attr, r=nrc

`TokenStream`-based attributes, paths in attribute and derive macro invocations

This PR
 - refactors `Attribute` to use  `Path` and `TokenStream` instead of `MetaItem`.
 - supports macro invocation paths for attribute procedural macros.
   - e.g. `#[::foo::attr_macro] struct S;`, `#[cfg_attr(all(), foo::attr_macro)] struct S;`
 - supports macro invocation paths for derive procedural macros.
   - e.g. `#[derive(foo::Bar, super::Baz)] struct S;`
 - supports arbitrary tokens as arguments to attribute procedural macros.
   - e.g. `#[foo::attr_macro arbitrary + tokens] struct S;`
 - supports using arbitrary tokens in "inert attributes" with derive procedural macros.
   - e.g. `#[derive(Foo)] struct S(#[inert arbitrary + tokens] i32);`
where `#[proc_macro_derive(Foo, attributes(inert))]`

r? @nrc

13 files changed, 45 insertions, 43 deletions

diff --git a/src/test/compile-fail-fulldeps/proc-macro/proc-macro-attributes.rs b/src/test/compile-fail-fulldeps/proc-macro/proc-macro-attributes.rs
index 4ad1cf79d61..df881bedec1 100644
--- a/src/test/compile-fail-fulldeps/proc-macro/proc-macro-attributes.rs
+++ b/src/test/compile-fail-fulldeps/proc-macro/proc-macro-attributes.rs
@@ -20,6 +20,7 @@ extern crate derive_b;
 #[C] //~ ERROR: The attribute `C` is currently unknown to the compiler
 #[B(D)]
 #[B(E = "foo")]
+#[B arbitrary tokens] //~ expected one of `(` or `=`, found `arbitrary`
 struct B;
 
 fn main() {}
diff --git a/src/test/parse-fail/macro-attribute.rs b/src/test/compile-fail/macro-attribute.rs
index 18add7d011c..52f867fe913 100644
--- a/src/test/parse-fail/macro-attribute.rs
+++ b/src/test/compile-fail/macro-attribute.rs
@@ -8,7 +8,5 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
-
 #[doc = $not_there] //~ error: unexpected token: `$`
 fn main() { }
diff --git a/src/test/compile-fail/macro-with-seps-err-msg.rs b/src/test/compile-fail/macro-with-seps-err-msg.rs
index 6cc682bde99..c28e22d58f9 100644
--- a/src/test/compile-fail/macro-with-seps-err-msg.rs
+++ b/src/test/compile-fail/macro-with-seps-err-msg.rs
@@ -14,4 +14,5 @@ fn main() {
     globnar::brotz!(); //~ ERROR non-ident macro paths are experimental
     ::foo!(); //~ ERROR non-ident macro paths are experimental
     foo::<T>!(); //~ ERROR type parameters are not allowed on macros
+    #[derive(foo::Bar)] struct T; //~ ERROR non-ident macro paths are experimental
 }
diff --git a/src/test/compile-fail/malformed-derive-entry.rs b/src/test/compile-fail/malformed-derive-entry.rs
index 62dbc21495a..ac000628f2b 100644
--- a/src/test/compile-fail/malformed-derive-entry.rs
+++ b/src/test/compile-fail/malformed-derive-entry.rs
@@ -9,11 +9,11 @@
 // except according to those terms.
 
 #[derive(Copy(Bad))]
-//~^ ERROR malformed `derive` entry
+//~^ ERROR expected one of `)`, `,`, or `::`, found `(`
 struct Test1;
 
 #[derive(Copy="bad")]
-//~^ ERROR malformed `derive` entry
+//~^ ERROR expected one of `)`, `,`, or `::`, found `=`
 struct Test2;
 
 #[derive()]
diff --git a/src/test/compile-fail/suffixed-literal-meta.rs b/src/test/compile-fail/suffixed-literal-meta.rs
new file mode 100644
index 00000000000..bf55b7bdcb1
--- /dev/null
+++ b/src/test/compile-fail/suffixed-literal-meta.rs
@@ -0,0 +1,25 @@
+// Copyright 2012 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 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(attr_literals)]
+
+#[path = 1usize] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1u8] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1u16] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1u32] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1u64] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1isize] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1i8] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1i16] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1i32] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1i64] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1.0f32] //~ ERROR: suffixed literals are not allowed in attributes
+#[path = 1.0f64] //~ ERROR: suffixed literals are not allowed in attributes
+fn main() { }
diff --git a/src/test/parse-fail/attr-bad-meta.rs b/src/test/parse-fail/attr-bad-meta.rs
index 092adbf29e3..d57a813311b 100644
--- a/src/test/parse-fail/attr-bad-meta.rs
+++ b/src/test/parse-fail/attr-bad-meta.rs
@@ -8,10 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
-
-// error-pattern:expected one of `=` or `]`
-
 // asterisk is bogus
-#[attr*]
+#[path*] //~ ERROR expected one of `(` or `=`
 mod m {}
diff --git a/src/test/parse-fail/suffixed-literal-meta.rs b/src/test/parse-fail/suffixed-literal-meta.rs
deleted file mode 100644
index 0e2840c69d3..00000000000
--- a/src/test/parse-fail/suffixed-literal-meta.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2012 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 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// compile-flags: -Z parse-only
-
-#[foo = 1usize] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1u8] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1u16] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1u32] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1u64] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1isize] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1i8] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1i16] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1i32] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1i64] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1.0f32] //~ ERROR: suffixed literals are not allowed in attributes
-#[foo = 1.0f64] //~ ERROR: suffixed literals are not allowed in attributes
-fn main() { }
diff --git a/src/test/run-pass-fulldeps/proc-macro/attr-args.rs b/src/test/run-pass-fulldeps/proc-macro/attr-args.rs
index d28d75d81a2..8a9fdd75367 100644
--- a/src/test/run-pass-fulldeps/proc-macro/attr-args.rs
+++ b/src/test/run-pass-fulldeps/proc-macro/attr-args.rs
@@ -19,6 +19,6 @@ use attr_args::attr_with_args;
 #[attr_with_args(text = "Hello, world!")]
 fn foo() {}
 
-fn main() {
-    assert_eq!(foo(), "Hello, world!");
-}
+#[::attr_args::identity
+  fn main() { assert_eq!(foo(), "Hello, world!"); }]
+struct Dummy;
diff --git a/src/test/run-pass-fulldeps/proc-macro/auxiliary/attr-args.rs b/src/test/run-pass-fulldeps/proc-macro/auxiliary/attr-args.rs
index 6e1eb395a0a..989c77f1089 100644
--- a/src/test/run-pass-fulldeps/proc-macro/auxiliary/attr-args.rs
+++ b/src/test/run-pass-fulldeps/proc-macro/auxiliary/attr-args.rs
@@ -30,3 +30,8 @@ pub fn attr_with_args(args: TokenStream, input: TokenStream) -> TokenStream {
         fn foo() -> &'static str { "Hello, world!" }
     "#.parse().unwrap()
 }
+
+#[proc_macro_attribute]
+pub fn identity(attr_args: TokenStream, _: TokenStream) -> TokenStream {
+    attr_args
+}
diff --git a/src/test/run-pass-fulldeps/proc-macro/auxiliary/derive-b.rs b/src/test/run-pass-fulldeps/proc-macro/auxiliary/derive-b.rs
index bf793534d50..7b521f2b913 100644
--- a/src/test/run-pass-fulldeps/proc-macro/auxiliary/derive-b.rs
+++ b/src/test/run-pass-fulldeps/proc-macro/auxiliary/derive-b.rs
@@ -19,7 +19,7 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(B, attributes(B, C))]
 pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
-    assert!(input.contains("#[B]"));
+    assert!(input.contains("#[B arbitrary tokens]"));
     assert!(input.contains("struct B {"));
     assert!(input.contains("#[C]"));
     "".parse().unwrap()
diff --git a/src/test/run-pass-fulldeps/proc-macro/derive-b.rs b/src/test/run-pass-fulldeps/proc-macro/derive-b.rs
index f1e1626ddf8..995dc65729a 100644
--- a/src/test/run-pass-fulldeps/proc-macro/derive-b.rs
+++ b/src/test/run-pass-fulldeps/proc-macro/derive-b.rs
@@ -11,11 +11,12 @@
 // aux-build:derive-b.rs
 // ignore-stage1
 
-#[macro_use]
+#![feature(proc_macro)]
+
 extern crate derive_b;
 
-#[derive(Debug, PartialEq, B, Eq, Copy, Clone)]
-#[B]
+#[derive(Debug, PartialEq, derive_b::B, Eq, Copy, Clone)]
+#[cfg_attr(all(), B arbitrary tokens)]
 struct B {
     #[C]
     a: u64
diff --git a/src/test/ui/span/E0536.stderr b/src/test/ui/span/E0536.stderr
index c33b89953e2..b2da0c6a296 100644
--- a/src/test/ui/span/E0536.stderr
+++ b/src/test/ui/span/E0536.stderr
@@ -2,7 +2,7 @@ error[E0536]: expected 1 cfg-pattern
   --> $DIR/E0536.rs:11:7
    |
 11 | #[cfg(not())] //~ ERROR E0536
-   |       ^^^^^
+   |       ^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/span/E0537.stderr b/src/test/ui/span/E0537.stderr
index 9d66ddbaae3..29873943f44 100644
--- a/src/test/ui/span/E0537.stderr
+++ b/src/test/ui/span/E0537.stderr
@@ -2,7 +2,7 @@ error[E0537]: invalid predicate `unknown`
   --> $DIR/E0537.rs:11:7
    |
 11 | #[cfg(unknown())] //~ ERROR E0537
-   |       ^^^^^^^^^
+   |       ^^^^^^^
 
 error: aborting due to previous error