Parser will not suggest invalid expression when use public

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -22,7 +22,7 @@ use rustc_errors::{
 use rustc_errors::{pluralize, struct_span_err, Diagnostic, ErrorGuaranteed};
 use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{kw, Ident};
+use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{Span, SpanSnippetError, DUMMY_SP};
 use std::ops::{Deref, DerefMut};
 
@@ -977,15 +977,6 @@ impl<'a> Parser<'a> {
         let mut err = self.struct_span_err(self.token.span, &msg_exp);
 
         if let TokenKind::Ident(symbol, _) = &self.prev_token.kind {
-            if symbol.as_str() == "public" {
-                err.span_suggestion_short(
-                    self.prev_token.span,
-                    "write `pub` instead of `public` to make the item public",
-                    "pub",
-                    appl,
-                );
-            }
-
             if ["def", "fun", "func", "function"].contains(&symbol.as_str()) {
                 err.span_suggestion_short(
                     self.prev_token.span,
@@ -996,6 +987,19 @@ impl<'a> Parser<'a> {
             }
         }
 
+        // `pub` may be used for an item or `pub(crate)`
+        if self.prev_token.is_ident_named(sym::public)
+            && (self.token.can_begin_item()
+                || self.token.kind == TokenKind::OpenDelim(Delimiter::Parenthesis))
+        {
+            err.span_suggestion_short(
+                self.prev_token.span,
+                "write `pub` instead of `public` to make the item public",
+                "pub",
+                appl,
+            );
+        }
+
         // Add suggestion for a missing closing angle bracket if '>' is included in expected_tokens
         // there are unclosed angle brackets
         if self.unmatched_angle_bracket_count > 0

compiler/rustc_span/src/symbol.rs

@@ -1118,6 +1118,7 @@ symbols! {
         ptr_offset_from_unsigned,
         pub_macro_rules,
         pub_restricted,
+        public,
         pure,
         pushpop_unsafe,
         qreg,

src/test/ui/parser/public-instead-of-pub-1.fixed

@@ -0,0 +1,11 @@
+// Checks what happens when `public` is used instead of the correct, `pub`
+// run-rustfix
+
+pub enum Test {
+    //~^ ERROR expected one of `!` or `::`, found keyword `enum`
+    //~^^ HELP write `pub` instead of `public` to make the item public
+    A,
+    B,
+}
+
+fn main() { }

src/test/ui/parser/public-instead-of-pub-1.rs

@@ -0,0 +1,11 @@
+// Checks what happens when `public` is used instead of the correct, `pub`
+// run-rustfix
+
+public enum Test {
+    //~^ ERROR expected one of `!` or `::`, found keyword `enum`
+    //~^^ HELP write `pub` instead of `public` to make the item public
+    A,
+    B,
+}
+
+fn main() { }

src/test/ui/parser/public-instead-of-pub-1.stderr

@@ -0,0 +1,13 @@
+error: expected one of `!` or `::`, found keyword `enum`
+  --> $DIR/public-instead-of-pub-1.rs:4:8
+   |
+LL | public enum Test {
+   |        ^^^^ expected one of `!` or `::`
+   |
+help: write `pub` instead of `public` to make the item public
+   |
+LL | pub enum Test {
+   | ~~~
+
+error: aborting due to previous error
+

src/test/ui/parser/public-instead-of-pub-2.rs

@@ -0,0 +1,7 @@
+// Checks what happens when `public` is used instead of the correct, `pub`
+// Won't give help message for this case
+
+public let x = 1;
+//~^ ERROR expected one of `!` or `::`, found keyword `let`
+
+fn main() { }

src/test/ui/parser/public-instead-of-pub-2.stderr

@@ -0,0 +1,8 @@
+error: expected one of `!` or `::`, found keyword `let`
+  --> $DIR/public-instead-of-pub-2.rs:4:8
+   |
+LL | public let x = 1;
+   |        ^^^ expected one of `!` or `::`
+
+error: aborting due to previous error
+