[experiment] Expand macros in inert key-value attributes

src/librustc/hir/lowering/expr.rs

@@ -192,7 +192,7 @@ impl LoweringContext<'_> {
             hir_id: self.lower_node_id(e.id),
             kind,
             span: e.span,
-            attrs: e.attrs.clone(),
+            attrs: self.lower_attrs_extendable(&e.attrs).into(),
         }
     }
 

src/librustc_parse/parser/mod.rs

@@ -15,6 +15,7 @@ use crate::{Directory, DirectoryOwnership};
 use crate::lexer::UnmatchedBrace;
 
 use rustc_errors::{PResult, Applicability, DiagnosticBuilder, FatalError};
+use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::thin_vec::ThinVec;
 use syntax::ast::{self, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Extern, Ident, StrLit};
 use syntax::ast::{IsAsync, MacArgs, MacDelimiter, Mutability, Visibility, VisibilityKind, Unsafety};
@@ -1028,22 +1029,10 @@ impl<'a> Parser<'a> {
         } else if !delimited_only {
             if self.eat(&token::Eq) {
                 let eq_span = self.prev_span;
-                let mut is_interpolated_expr = false;
-                if let token::Interpolated(nt) = &self.token.kind {
-                    if let token::NtExpr(..) = **nt {
-                        is_interpolated_expr = true;
-                    }
-                }
-                let token_tree = if is_interpolated_expr {
-                    // We need to accept arbitrary interpolated expressions to continue
-                    // supporting things like `doc = $expr` that work on stable.
-                    // Non-literal interpolated expressions are rejected after expansion.
-                    self.parse_token_tree()
-                } else {
-                    self.parse_unsuffixed_lit()?.token_tree()
-                };
-
-                MacArgs::Eq(eq_span, token_tree.into())
+                let expr = self.parse_expr()?;
+                let span = expr.span;
+                let kind = token::Interpolated(Lrc::new(token::NtExpr(expr)));
+                MacArgs::Eq(eq_span, TokenTree::token(kind, span).into())
             } else {
                 MacArgs::Empty
             }

src/test/rustdoc/external-doc.rs

@@ -6,3 +6,10 @@
 #[doc(include = "auxiliary/external-doc.md")]
 /// ## Inline Docs
 pub struct CanHasDocs;
+
+// @has external_doc/struct.IncludeStrDocs.html
+// @has - '//h1' 'External Docs'
+// @has - '//h2' 'Inline Docs'
+#[doc = include_str!("auxiliary/external-doc.md")]
+/// ## Inline Docs
+pub struct IncludeStrDocs;

src/test/ui/attr-eq-token-tree.rs

@@ -1,2 +1,2 @@
-#[my_attr = !] //~ ERROR unexpected token: `!`
+#[my_attr = !] //~ ERROR expected expression, found `]`
 fn main() {}

src/test/ui/attr-eq-token-tree.stderr

@@ -1,8 +1,8 @@
-error: unexpected token: `!`
-  --> $DIR/attr-eq-token-tree.rs:1:13
+error: expected expression, found `]`
+  --> $DIR/attr-eq-token-tree.rs:1:14
    |
 LL | #[my_attr = !]
-   |             ^
+   |              ^ expected expression
 
 error: aborting due to previous error
 

src/test/ui/macros/macro-attribute.rs

@@ -1,2 +1,2 @@
-#[doc = $not_there] //~ ERROR unexpected token: `$`
+#[doc = $not_there] //~ ERROR expected expression, found `$`
 fn main() { }

src/test/ui/macros/macro-attribute.stderr

@@ -1,8 +1,8 @@
-error: unexpected token: `$`
+error: expected expression, found `$`
   --> $DIR/macro-attribute.rs:1:9
    |
 LL | #[doc = $not_there]
-   |         ^
+   |         ^ expected expression
 
 error: aborting due to previous error
 

src/test/ui/malformed/malformed-interpolated.rs

@@ -2,16 +2,15 @@
 
 macro_rules! check {
     ($expr: expr) => (
-        #[rustc_dummy = $expr] //~ ERROR unexpected token: `-0`
-                               //~| ERROR unexpected token: `0 + 0`
+        #[rustc_dummy = $expr]
         use main as _;
     );
 }
 
 check!("0"); // OK
 check!(0); // OK
 check!(0u8); //~ ERROR suffixed literals are not allowed in attributes
-check!(-0); // ERROR, see above
-check!(0 + 0); // ERROR, see above
+check!(-0); //~ ERROR unexpected token: `-0`
+check!(0 + 0); //~ ERROR unexpected token: `0 + 0`
 
 fn main() {}

src/test/ui/malformed/malformed-interpolated.stderr

@@ -1,28 +1,22 @@
 error: suffixed literals are not allowed in attributes
-  --> $DIR/malformed-interpolated.rs:13:8
+  --> $DIR/malformed-interpolated.rs:12:8
    |
 LL | check!(0u8);
    |        ^^^
    |
    = help: instead of using a suffixed literal (1u8, 1.0f32, etc.), use an unsuffixed version (1, 1.0, etc.).
 
 error: unexpected token: `-0`
-  --> $DIR/malformed-interpolated.rs:5:25
+  --> $DIR/malformed-interpolated.rs:13:8
    |
-LL |         #[rustc_dummy = $expr]
-   |                         ^^^^^
-...
-LL | check!(-0); // ERROR, see above
-   | ----------- in this macro invocation
+LL | check!(-0);
+   |        ^^
 
 error: unexpected token: `0 + 0`
-  --> $DIR/malformed-interpolated.rs:5:25
+  --> $DIR/malformed-interpolated.rs:14:8
    |
-LL |         #[rustc_dummy = $expr]
-   |                         ^^^^^
-...
-LL | check!(0 + 0); // ERROR, see above
-   | -------------- in this macro invocation
+LL | check!(0 + 0);
+   |        ^^^^^
 
 error: aborting due to 3 previous errors
 

src/test/ui/parser/attr-bad-meta-2.rs

@@ -1,2 +1,2 @@
-#[path =] //~ ERROR unexpected token: `]`
+#[path =] //~ ERROR expected expression, found `]`
 mod m {}

src/test/ui/parser/attr-bad-meta-2.stderr

@@ -1,8 +1,8 @@
-error: unexpected token: `]`
+error: expected expression, found `]`
   --> $DIR/attr-bad-meta-2.rs:1:9
    |
 LL | #[path =]
-   |         ^
+   |         ^ expected expression
 
 error: aborting due to previous error
 

src/test/ui/proc-macro/attributes-included.rs

@@ -10,11 +10,11 @@ use attributes_included::*;
 #[bar]
 #[inline]
 /// doc
-#[foo]
+#[foo] //~ WARN unused variable: `a`
 #[inline]
 /// doc
 fn foo() {
-    let a: i32 = "foo"; //~ WARN: unused variable
+    let a: i32 = "foo";
 }
 
 fn main() {

src/test/ui/proc-macro/attributes-included.stderr

@@ -1,8 +1,8 @@
 warning: unused variable: `a`
-  --> $DIR/attributes-included.rs:17:9
+  --> $DIR/attributes-included.rs:13:1
    |
-LL |     let a: i32 = "foo";
-   |         ^ help: consider prefixing with an underscore: `_a`
+LL | #[foo]
+   | ^^^^^^ help: consider prefixing with an underscore: `_a`
    |
 note: lint level defined here
   --> $DIR/attributes-included.rs:4:9