Add deprecation warning for --passes

Author: inashivb

src/librustdoc/config.rs

@@ -327,6 +327,19 @@ impl Options {
             return Err(0);
         }
 
+        let color = config::parse_color(matches);
+        let config::JsonConfig { json_rendered, json_unused_externs, .. } =
+            config::parse_json(matches);
+        let error_format = config::parse_error_format(matches, color, json_rendered);
+
+        let codegen_options = CodegenOptions::build(matches, error_format);
+        let debugging_opts = DebuggingOptions::build(matches, error_format);
+
+        let diag = new_handler(error_format, None, &debugging_opts);
+
+        // check for deprecated options
+        check_deprecated_options(matches, &diag);
+
         if matches.opt_strs("passes") == ["list"] {
             println!("Available passes for running rustdoc:");
             for pass in passes::PASSES {
@@ -359,19 +372,6 @@ impl Options {
             return Err(0);
         }
 
-        let color = config::parse_color(matches);
-        let config::JsonConfig { json_rendered, json_unused_externs, .. } =
-            config::parse_json(matches);
-        let error_format = config::parse_error_format(matches, color, json_rendered);
-
-        let codegen_options = CodegenOptions::build(matches, error_format);
-        let debugging_opts = DebuggingOptions::build(matches, error_format);
-
-        let diag = new_handler(error_format, None, &debugging_opts);
-
-        // check for deprecated options
-        check_deprecated_options(matches, &diag);
-
         let mut emit = Vec::new();
         for list in matches.opt_strs("emit") {
             for kind in list.split(',') {