Improve `-Z crate-attr` diagnostics

- Show the `#![ ... ]` in the span (to make it clear that it should not
  be included in the CLI argument)
- Show more detailed errors when the crate has valid token trees but
  invalid syntax.
  Previously, `crate-attr=feature(foo),feature(bar)` would just say
  "invalid crate attribute" and point at the comma. Now, it explicitly
  says that the comma was unexpected, which is useful when using
  `--error-format=short`. It also fixes the column to show the correct
  span.
- Recover from parse errors. Previously we would abort immediately on
  syntax errors; now we go on to try and type-check the rest of the
  crate.

The new diagnostic code also happens to be slightly shorter.

2 files changed, 25 insertions, 39 deletions

diff --git a/compiler/rustc_builtin_macros/src/cmdline_attrs.rs b/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
index 6afd8c4b43b..423b6a15b64 100644
--- a/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
+++ b/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
@@ -1,44 +1,37 @@
 //! Attributes injected into the crate root from command line using `-Z crate-attr`.
 
-use rustc_ast::attr::mk_attr;
-use rustc_ast::{self as ast, AttrItem, AttrStyle, token};
-use rustc_parse::parser::ForceCollect;
-use rustc_parse::{new_parser_from_source_str, unwrap_or_emit_fatal};
+use rustc_ast::{self as ast};
+use rustc_errors::Diag;
+use rustc_parse::parser::attr::InnerAttrPolicy;
+use rustc_parse::{parse_in, source_str_to_stream};
 use rustc_session::parse::ParseSess;
 use rustc_span::FileName;
 
-use crate::errors;
-
 pub fn inject(krate: &mut ast::Crate, psess: &ParseSess, attrs: &[String]) {
     for raw_attr in attrs {
-        let mut parser = unwrap_or_emit_fatal(new_parser_from_source_str(
-            psess,
-            FileName::cli_crate_attr_source_code(raw_attr),
-            raw_attr.clone(),
-        ));
-
-        let start_span = parser.token.span;
-        let AttrItem { unsafety, path, args, tokens: _ } =
-            match parser.parse_attr_item(ForceCollect::No) {
-                Ok(ai) => ai,
-                Err(err) => {
+        let source = format!("#![{raw_attr}]");
+        let parse = || -> Result<ast::Attribute, Vec<Diag<'_>>> {
+            let tokens = source_str_to_stream(
+                psess,
+                FileName::cli_crate_attr_source_code(raw_attr),
+                source,
+                None,
+            )?;
+            parse_in(psess, tokens, "<crate attribute>", |p| {
+                p.parse_attribute(InnerAttrPolicy::Permitted)
+            })
+            .map_err(|e| vec![e])
+        };
+        let meta = match parse() {
+            Ok(meta) => meta,
+            Err(errs) => {
+                for err in errs {
                     err.emit();
-                    continue;
                 }
-            };
-        let end_span = parser.token.span;
-        if parser.token != token::Eof {
-            psess.dcx().emit_err(errors::InvalidCrateAttr { span: start_span.to(end_span) });
-            continue;
-        }
+                continue;
+            }
+        };
 
-        krate.attrs.push(mk_attr(
-            &psess.attr_id_generator,
-            AttrStyle::Inner,
-            unsafety,
-            path,
-            args,
-            start_span.to(end_span),
-        ));
+        krate.attrs.push(meta);
     }
 }
diff --git a/compiler/rustc_builtin_macros/src/errors.rs b/compiler/rustc_builtin_macros/src/errors.rs
index 4bbe212f429..c2b1dff4cf1 100644
--- a/compiler/rustc_builtin_macros/src/errors.rs
+++ b/compiler/rustc_builtin_macros/src/errors.rs
@@ -110,13 +110,6 @@ pub(crate) struct ProcMacro {
 }
 
 #[derive(Diagnostic)]
-#[diag(builtin_macros_invalid_crate_attribute)]
-pub(crate) struct InvalidCrateAttr {
-    #[primary_span]
-    pub(crate) span: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(builtin_macros_non_abi)]
 pub(crate) struct NonABI {
     #[primary_span]