Recover from pub let inside function

Author: obeis

compiler/rustc_parse/locales/en-US.ftl

@@ -439,6 +439,9 @@ parse_visibility_not_followed_by_item = visibility `{$vis}` is not followed by a
     .label = the visibility
     .help = you likely meant to define an item, e.g., `{$vis} fn foo() {"{}"}`
 
+parse_visibility_followed_by_let = visibility does not apply to `let` statement
+    .suggestion = remove pub
+
 parse_default_not_followed_by_item = `default` is not followed by an item
     .label = the `default` qualifier
     .note = only `fn`, `const`, `type`, or `impl` items may be prefixed by `default`

compiler/rustc_parse/src/errors.rs

@@ -1403,6 +1403,14 @@ pub(crate) struct VisibilityNotFollowedByItem {
     pub vis: Visibility,
 }
 
+#[derive(Diagnostic)]
+#[diag(parse_visibility_followed_by_let)]
+pub(crate) struct VisibilityFollowedByLet {
+    #[primary_span]
+    #[suggestion(code = "let", applicability = "machine-applicable")]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(parse_default_not_followed_by_item)]
 #[note]

compiler/rustc_parse/src/parser/stmt.rs

@@ -111,6 +111,11 @@ impl<'a> Parser<'a> {
             // Do not attempt to parse an expression if we're done here.
             self.error_outer_attrs(attrs);
             self.mk_stmt(lo, StmtKind::Empty)
+        } else if self.prev_token.is_keyword(kw::Pub) && self.token.is_keyword(kw::Let) {
+            let err = self.sess.create_err(errors::VisibilityFollowedByLet {
+                span: self.prev_token.span.to(self.token.span),
+            });
+            return Err(err);
         } else if self.token != token::CloseDelim(Delimiter::Brace) {
             // Remainder are line-expr stmts.
             let e = match force_collect {