Handle macro invocation in attribute during parse

compiler/rustc_ast/src/ast.rs

@@ -1235,6 +1235,19 @@ pub enum StmtKind {
     MacCall(Box<MacCallStmt>),
 }
 
+impl StmtKind {
+    pub fn descr(&self) -> &'static str {
+        match self {
+            StmtKind::Let(_) => "local",
+            StmtKind::Item(_) => "item",
+            StmtKind::Expr(_) => "expression",
+            StmtKind::Semi(_) => "statement",
+            StmtKind::Empty => "semicolon",
+            StmtKind::MacCall(_) => "macro",
+        }
+    }
+}
+
 #[derive(Clone, Encodable, Decodable, Debug, Walkable)]
 pub struct MacCallStmt {
     pub mac: Box<MacCall>,

compiler/rustc_attr_parsing/messages.ftl

@@ -200,6 +200,7 @@ attr_parsing_invalid_attr_unsafe = `{$name}` is not an unsafe attribute
 attr_parsing_invalid_meta_item = expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found {$descr}
     .remove_neg_sugg = negative numbers are not literals, try removing the `-` sign
     .quote_ident_sugg = surround the identifier with quotation marks to make it into a string literal
+    .label = {$descr}s are not allowed here
 
 attr_parsing_suffixed_literal_in_attribute = suffixed literals are not allowed in attributes
     .help = instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), use an unsuffixed version (`1`, `1.0`, etc.)

compiler/rustc_attr_parsing/src/parser.rs

@@ -8,12 +8,14 @@ use std::fmt::{Debug, Display};
 
 use rustc_ast::token::{self, Delimiter, MetaVarKind};
 use rustc_ast::tokenstream::TokenStream;
-use rustc_ast::{AttrArgs, DelimArgs, Expr, ExprKind, LitKind, MetaItemLit, NormalAttr, Path};
+use rustc_ast::{
+    AttrArgs, DelimArgs, Expr, ExprKind, LitKind, MetaItemLit, NormalAttr, Path, StmtKind, UnOp,
+};
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Diag, PResult};
 use rustc_hir::{self as hir, AttrPath};
 use rustc_parse::exp;
-use rustc_parse::parser::{Parser, PathStyle, token_descr};
+use rustc_parse::parser::{ForceCollect, Parser, PathStyle, token_descr};
 use rustc_session::errors::{create_lit_error, report_lit_error};
 use rustc_session::parse::ParseSess;
 use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol, sym};
@@ -476,33 +478,55 @@ impl<'a, 'sess> MetaItemListParserContext<'a, 'sess> {
             descr: token_descr(&self.parser.token),
             quote_ident_sugg: None,
             remove_neg_sugg: None,
+            label: None,
         };
 
+        if let token::OpenInvisible(_) = self.parser.token.kind {
+            // Do not attempt to suggest anything when encountered as part of a macro expansion.
+            return self.parser.dcx().create_err(err);
+        }
+
         // Suggest quoting idents, e.g. in `#[cfg(key = value)]`. We don't use `Token::ident` and
         // don't `uninterpolate` the token to avoid suggesting anything butchered or questionable
         // when macro metavariables are involved.
-        if self.parser.prev_token == token::Eq
-            && let token::Ident(..) = self.parser.token.kind
-        {
-            let before = self.parser.token.span.shrink_to_lo();
-            while let token::Ident(..) = self.parser.token.kind {
-                self.parser.bump();
+        let snapshot = self.parser.create_snapshot_for_diagnostic();
+        let stmt = self.parser.parse_stmt_without_recovery(false, ForceCollect::No, false);
+        match stmt {
+            Ok(Some(stmt)) => {
+                // The user tried to write something like
+                // `#[deprecated(note = concat!("a", "b"))]`.
+                err.descr = stmt.kind.descr().to_string();
+                err.label = Some(stmt.span);
+                err.span = stmt.span;
+                if let StmtKind::Expr(expr) = &stmt.kind
+                    && let ExprKind::Unary(UnOp::Neg, val) = &expr.kind
+                    && let ExprKind::Lit(_) = val.kind
+                {
+                    err.remove_neg_sugg = Some(InvalidMetaItemRemoveNegSugg {
+                        negative_sign: expr.span.until(val.span),
+                    });
+                } else if let StmtKind::Expr(expr) = &stmt.kind
+                    && let ExprKind::Path(None, Path { segments, .. }) = &expr.kind
+                    && segments.len() == 1
+                {
+                    while let token::Ident(..) | token::Literal(_) | token::Dot =
+                        self.parser.token.kind
+                    {
+                        // We've got a word, so we try to consume the rest of a potential sentence.
+                        // We include `.` to correctly handle things like `A sentence here.`.
+                        self.parser.bump();
+                    }
+                    err.quote_ident_sugg = Some(InvalidMetaItemQuoteIdentSugg {
+                        before: expr.span.shrink_to_lo(),
+                        after: self.parser.prev_token.span.shrink_to_hi(),
+                    });
+                }
+            }
+            Ok(None) => {}
+            Err(e) => {
+                e.cancel();
+                self.parser.restore_snapshot(snapshot);
             }
-            err.quote_ident_sugg = Some(InvalidMetaItemQuoteIdentSugg {
-                before,
-                after: self.parser.prev_token.span.shrink_to_hi(),
-            });
-        }
-
-        if self.parser.token == token::Minus
-            && self
-                .parser
-                .look_ahead(1, |t| matches!(t.kind, rustc_ast::token::TokenKind::Literal { .. }))
-        {
-            err.remove_neg_sugg =
-                Some(InvalidMetaItemRemoveNegSugg { negative_sign: self.parser.token.span });
-            self.parser.bump();
-            self.parser.bump();
         }
 
         self.parser.dcx().create_err(err)

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -829,6 +829,8 @@ pub(crate) struct InvalidMetaItem {
     pub quote_ident_sugg: Option<InvalidMetaItemQuoteIdentSugg>,
     #[subdiagnostic]
     pub remove_neg_sugg: Option<InvalidMetaItemRemoveNegSugg>,
+    #[label]
+    pub label: Option<Span>,
 }
 
 #[derive(Subdiagnostic)]

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -278,7 +278,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Replace `self` with `snapshot.parser`.
-    pub(super) fn restore_snapshot(&mut self, snapshot: SnapshotParser<'a>) {
+    pub fn restore_snapshot(&mut self, snapshot: SnapshotParser<'a>) {
         *self = snapshot.parser;
     }
 

tests/ui/attributes/malformed-fn-align.rs

@@ -26,7 +26,7 @@ fn f3() {}
 #[repr(align(16))] //~ ERROR `#[repr(align(...))]` is not supported on functions
 fn f4() {}
 
-#[rustc_align(-1)] //~ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
+#[rustc_align(-1)] //~ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
 fn f5() {}
 
 #[rustc_align(3)] //~ ERROR invalid alignment value: not a power of two

tests/ui/attributes/malformed-fn-align.stderr

@@ -37,11 +37,11 @@ error[E0589]: invalid alignment value: not a power of two
 LL | #[rustc_align(0)]
    |               ^
 
-error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
   --> $DIR/malformed-fn-align.rs:29:15
    |
 LL | #[rustc_align(-1)]
-   |               ^
+   |               ^^ expressions are not allowed here
    |
 help: negative numbers are not literals, try removing the `-` sign
    |

tests/ui/deprecation/issue-66340-deprecated-attr-non-meta-grammar.rs

@@ -7,5 +7,5 @@ fn main() {
 }
 
 #[deprecated(note = test)]
-//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `test`
+//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
 fn foo() {}

tests/ui/deprecation/issue-66340-deprecated-attr-non-meta-grammar.stderr

@@ -1,8 +1,8 @@
-error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `test`
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
   --> $DIR/issue-66340-deprecated-attr-non-meta-grammar.rs:9:21
    |
 LL | #[deprecated(note = test)]
-   |                     ^^^^
+   |                     ^^^^ expressions are not allowed here
    |
 help: surround the identifier with quotation marks to make it into a string literal
    |

tests/ui/parser/attribute/attr-bad-meta-4.rs

@@ -9,7 +9,7 @@ macro_rules! mac {
 mac!(an(arbitrary token stream));
 
 #[cfg(feature = -1)]
-//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
+//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
 fn handler() {}
 
 fn main() {}

tests/ui/parser/attribute/attr-bad-meta-4.stderr

@@ -1,8 +1,8 @@
-error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
   --> $DIR/attr-bad-meta-4.rs:11:17
    |
 LL | #[cfg(feature = -1)]
-   |                 ^
+   |                 ^^ expressions are not allowed here
    |
 help: negative numbers are not literals, try removing the `-` sign
    |

tests/ui/parser/attribute/attr-unquoted-ident.rs

@@ -4,22 +4,29 @@
 
 fn main() {
     #[cfg(key=foo)]
-    //~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `foo`
-    //~| HELP surround the identifier with quotation marks to make it into a string literal
+    //~^ ERROR: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
+    //~| HELP: surround the identifier with quotation marks to make it into a string literal
+    //~| NOTE: expressions are not allowed here
     println!();
     #[cfg(key="bar")]
     println!();
     #[cfg(key=foo bar baz)]
-    //~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `foo`
-    //~| HELP surround the identifier with quotation marks to make it into a string literal
+    //~^ ERROR: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
+    //~| HELP: surround the identifier with quotation marks to make it into a string literal
+    //~| NOTE: expressions are not allowed here
+    println!();
+    #[cfg(key=foo 1 bar 2.0 baz.)]
+    //~^ ERROR: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
+    //~| HELP: surround the identifier with quotation marks to make it into a string literal
+    //~| NOTE: expressions are not allowed here
     println!();
 }
 
 // Don't suggest surrounding `$name` or `nickname` with quotes:
 
 macro_rules! make {
     ($name:ident) => { #[doc(alias = $name)] pub struct S; }
-    //~^ ERROR expected unsuffixed literal, found identifier `nickname`
+    //~^ ERROR: expected unsuffixed literal, found identifier `nickname`
 }
 
-make!(nickname); //~ NOTE in this expansion
+make!(nickname); //~ NOTE: in this expansion

tests/ui/parser/attribute/attr-unquoted-ident.stderr

@@ -1,27 +1,38 @@
-error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `foo`
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
   --> $DIR/attr-unquoted-ident.rs:6:15
    |
 LL |     #[cfg(key=foo)]
-   |               ^^^
+   |               ^^^ expressions are not allowed here
    |
 help: surround the identifier with quotation marks to make it into a string literal
    |
 LL |     #[cfg(key="foo")]
    |               +   +
 
-error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `foo`
-  --> $DIR/attr-unquoted-ident.rs:12:15
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
+  --> $DIR/attr-unquoted-ident.rs:13:15
    |
 LL |     #[cfg(key=foo bar baz)]
-   |               ^^^
+   |               ^^^ expressions are not allowed here
    |
 help: surround the identifier with quotation marks to make it into a string literal
    |
 LL |     #[cfg(key="foo bar baz")]
    |               +           +
 
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
+  --> $DIR/attr-unquoted-ident.rs:18:15
+   |
+LL |     #[cfg(key=foo 1 bar 2.0 baz.)]
+   |               ^^^ expressions are not allowed here
+   |
+help: surround the identifier with quotation marks to make it into a string literal
+   |
+LL |     #[cfg(key="foo 1 bar 2.0 baz.")]
+   |               +                  +
+
 error: expected unsuffixed literal, found identifier `nickname`
-  --> $DIR/attr-unquoted-ident.rs:21:38
+  --> $DIR/attr-unquoted-ident.rs:28:38
    |
 LL |     ($name:ident) => { #[doc(alias = $name)] pub struct S; }
    |                                      ^^^^^
@@ -31,5 +42,5 @@ LL | make!(nickname);
    |
    = note: this error originates in the macro `make` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 

tests/ui/parser/macro/expr-in-attribute.rs

@@ -0,0 +1,9 @@
+// Test for #146325.
+// Ensure that when we encounter an expr invocation in an attribute, we don't suggest nonsense.
+
+#[deprecated(note = a!=b)]
+struct X;
+//~^^ ERROR: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
+//~| NOTE: expressions are not allowed here
+
+fn main() {}

tests/ui/parser/macro/expr-in-attribute.stderr

@@ -0,0 +1,8 @@
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found expression
+  --> $DIR/expr-in-attribute.rs:4:21
+   |
+LL | #[deprecated(note = a!=b)]
+   |                     ^^^^ expressions are not allowed here
+
+error: aborting due to 1 previous error
+

tests/ui/parser/macro/macro-in-attribute.rs

@@ -0,0 +1,9 @@
+// Test for #146325.
+// Ensure that when we encounter a macro invocation in an attribute, we don't suggest nonsense.
+
+#[deprecated(note = concat!("a", "b"))]
+struct X;
+//~^^ ERROR: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found
+//~| NOTE: macros are not allowed here
+
+fn main() {}

tests/ui/parser/macro/macro-in-attribute.stderr

@@ -0,0 +1,8 @@
+error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found macro
+  --> $DIR/macro-in-attribute.rs:4:21
+   |
+LL | #[deprecated(note = concat!("a", "b"))]
+   |                     ^^^^^^^^^^^^^^^^^ macros are not allowed here
+
+error: aborting due to 1 previous error
+