Move malformed attribute code to a function and fix inner attribute suggestion.

Moving to a dedicated function in preparation for other validation.

The suggestion given didn't consider if it was an inner attribute.

compiler/rustc_parse/src/validate_attr.rs

@@ -91,27 +91,39 @@ pub fn check_builtin_attribute(
     // Some special attributes like `cfg` must be checked
     // before the generic check, so we skip them here.
     let should_skip = |name| name == sym::cfg;
-    // Some of previously accepted forms were used in practice,
-    // report them as warnings for now.
-    let should_warn = |name| {
-        name == sym::doc
-            || name == sym::ignore
-            || name == sym::inline
-            || name == sym::link
-            || name == sym::test
-            || name == sym::bench
-    };
 
     match parse_meta(sess, attr) {
         Ok(meta) => {
             if !should_skip(name) && !is_attr_template_compatible(&template, &meta.kind) {
+                emit_malformed_attribute(sess, attr, name, template);
+            }
+        }
+        Err(mut err) => {
+            err.emit();
+        }
+    }
+}
+
+fn emit_malformed_attribute(
+    sess: &ParseSess,
+    attr: &Attribute,
+    name: Symbol,
+    template: AttributeTemplate,
+) {
+    // Some of previously accepted forms were used in practice,
+    // report them as warnings for now.
+    let should_warn = |name| {
+        matches!(name, sym::doc | sym::ignore | sym::inline | sym::link | sym::test | sym::bench)
+    };
+
     let error_msg = format!("malformed `{}` attribute input", name);
     let mut msg = "attribute must be of the form ".to_owned();
     let mut suggestions = vec![];
     let mut first = true;
+    let inner = if attr.style == ast::AttrStyle::Inner { "!" } else { "" };
     if template.word {
         first = false;
-                    let code = format!("#[{}]", name);
+        let code = format!("#{}[{}]", inner, name);
         msg.push_str(&format!("`{}`", &code));
         suggestions.push(code);
     }
@@ -120,7 +132,7 @@ pub fn check_builtin_attribute(
             msg.push_str(" or ");
         }
         first = false;
-                    let code = format!("#[{}({})]", name, descr);
+        let code = format!("#{}[{}({})]", inner, name, descr);
         msg.push_str(&format!("`{}`", &code));
         suggestions.push(code);
     }
@@ -128,22 +140,17 @@ pub fn check_builtin_attribute(
         if !first {
             msg.push_str(" or ");
         }
-                    let code = format!("#[{} = \"{}\"]", name, descr);
+        let code = format!("#{}[{} = \"{}\"]", inner, name, descr);
         msg.push_str(&format!("`{}`", &code));
         suggestions.push(code);
     }
     if should_warn(name) {
-                    sess.buffer_lint(
-                        &ILL_FORMED_ATTRIBUTE_INPUT,
-                        meta.span,
-                        ast::CRATE_NODE_ID,
-                        &msg,
-                    );
+        sess.buffer_lint(&ILL_FORMED_ATTRIBUTE_INPUT, attr.span, ast::CRATE_NODE_ID, &msg);
     } else {
         sess.span_diagnostic
-                        .struct_span_err(meta.span, &error_msg)
+            .struct_span_err(attr.span, &error_msg)
             .span_suggestions(
-                            meta.span,
+                attr.span,
                 if suggestions.len() == 1 {
                     "must be of the form"
                 } else {
@@ -154,10 +161,4 @@ pub fn check_builtin_attribute(
             )
             .emit();
     }
-            }
-        }
-        Err(mut err) => {
-            err.emit();
-        }
-    }
 }

src/test/ui/attributes/register-attr-tool-fail.stderr

@@ -30,13 +30,13 @@ error: malformed `register_attr` attribute input
   --> $DIR/register-attr-tool-fail.rs:4:1
    |
 LL | #![register_attr]
-   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[register_attr(attr1, attr2, ...)]`
+   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#![register_attr(attr1, attr2, ...)]`
 
 error: malformed `register_tool` attribute input
   --> $DIR/register-attr-tool-fail.rs:5:1
    |
 LL | #![register_tool]
-   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[register_tool(tool1, tool2, ...)]`
+   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#![register_tool(tool1, tool2, ...)]`
 
 error: aborting due to 6 previous errors
 

src/test/ui/gated-bad-feature.stderr

@@ -20,13 +20,13 @@ error: malformed `feature` attribute input
   --> $DIR/gated-bad-feature.rs:5:1
    |
 LL | #![feature]
-   | ^^^^^^^^^^^ help: must be of the form: `#[feature(name1, name1, ...)]`
+   | ^^^^^^^^^^^ help: must be of the form: `#![feature(name1, name1, ...)]`
 
 error: malformed `feature` attribute input
   --> $DIR/gated-bad-feature.rs:6:1
    |
 LL | #![feature = "foo"]
-   | ^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[feature(name1, name1, ...)]`
+   | ^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#![feature(name1, name1, ...)]`
 
 error: aborting due to 5 previous errors
 

src/test/ui/invalid_crate_type_syntax.stderr

@@ -2,7 +2,7 @@ error: malformed `crate_type` attribute input
   --> $DIR/invalid_crate_type_syntax.rs:2:1
    |
 LL | #![crate_type(lib)]
-   | ^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[crate_type = "bin|lib|..."]`
+   | ^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#![crate_type = "bin|lib|..."]`
 
 error: aborting due to previous error
 

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

@@ -14,7 +14,7 @@ error: malformed `deny` attribute input
   --> $DIR/lint-malformed.rs:1:1
    |
 LL | #![deny = "foo"]
-   | ^^^^^^^^^^^^^^^^ help: must be of the form: `#[deny(lint1, lint2, ..., /*opt*/ reason = "...")]`
+   | ^^^^^^^^^^^^^^^^ help: must be of the form: `#![deny(lint1, lint2, ..., /*opt*/ reason = "...")]`
 
 error[E0452]: malformed lint attribute input
   --> $DIR/lint-malformed.rs:2:10

src/test/ui/malformed/malformed-plugin-1.stderr

@@ -2,7 +2,7 @@ error: malformed `plugin` attribute input
   --> $DIR/malformed-plugin-1.rs:2:1
    |
 LL | #![plugin]
-   | ^^^^^^^^^^ help: must be of the form: `#[plugin(name)]`
+   | ^^^^^^^^^^ help: must be of the form: `#![plugin(name)]`
 
 warning: use of deprecated attribute `plugin`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
   --> $DIR/malformed-plugin-1.rs:2:1

src/test/ui/malformed/malformed-plugin-2.stderr

@@ -2,7 +2,7 @@ error: malformed `plugin` attribute input
   --> $DIR/malformed-plugin-2.rs:2:1
    |
 LL | #![plugin="bleh"]
-   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[plugin(name)]`
+   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#![plugin(name)]`
 
 warning: use of deprecated attribute `plugin`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
   --> $DIR/malformed-plugin-2.rs:2:1

src/test/ui/no_crate_type.stderr

@@ -2,7 +2,7 @@ error: malformed `crate_type` attribute input
   --> $DIR/no_crate_type.rs:2:1
    |
 LL | #![crate_type]
-   | ^^^^^^^^^^^^^^ help: must be of the form: `#[crate_type = "bin|lib|..."]`
+   | ^^^^^^^^^^^^^^ help: must be of the form: `#![crate_type = "bin|lib|..."]`
 
 error: aborting due to previous error