Various improvements for test output

src/lib.rs

@@ -460,7 +460,7 @@ impl<'b, T: Write + 'b> Session<'b, T> {
     }
 
     /// The main entry point for Rustfmt. Formats the given input according to the
-    /// given config. `out` is only necessary if required by the configuration.
+    /// session's config.
     pub fn format(&mut self, input: Input) -> Result<FormatReport, ErrorKind> {
         self.format_input_inner(input, false)
     }

src/test/mod.rs

@@ -19,7 +19,7 @@ use crate::{
 };
 
 use rustfmt_config_proc_macro::nightly_only_test;
-use tracing::{debug, warn};
+use tracing::debug;
 
 mod configuration_snippet;
 mod mod_resolver;
@@ -534,7 +534,9 @@ fn stdin_parser_panic_caught() {
     // See issue #3239.
     for text in ["{", "}"].iter().cloned().map(String::from) {
         let mut buf = vec![];
-        let mut session = Session::new(Default::default(), Some(&mut buf));
+        let mut config = Config::default();
+        config.set().show_parse_errors(false);
+        let mut session = Session::new(config, Some(&mut buf));
         let _ = session.format(Input::Text(text));
 
         assert!(session.has_parsing_errors());
@@ -774,9 +776,6 @@ fn read_config(filename: &Path) -> Config {
     for (key, val) in &sig_comments {
         if key != "target" && key != "config" && key != "unstable" {
             config.override_value(key, val);
-            if config.is_default(key) {
-                warn!("Default value {} used explicitly for {}", val, key);
-            }
         }
     }
 

tests/parser/issue-4126/lib.rs

@@ -1 +1,3 @@
+// rustfmt-show_parse_errors: false
+
 mod invalid;

tests/parser/issue_4418.rs

@@ -1 +1,3 @@
-}
+// rustfmt-show_parse_errors: false
+
+}

tests/parser/stashed-diag.rs

@@ -1,3 +1,5 @@
+// rustfmt-show_parse_errors: false
+
 #![u={static N;}]
 
 fn main() {}

tests/parser/stashed-diag2.rs

@@ -1,3 +1,5 @@
+// rustfmt-show_parse_errors: false
+
 trait Trait<'1> { s> {}
 
 fn main() {}

tests/parser/unclosed-delims/issue_4466.rs

@@ -1,3 +1,5 @@
+// rustfmt-show_parse_errors: false
+
 fn main() {
     if true {
         println!("answer: {}", a_func();
@@ -8,4 +10,4 @@ fn main() {
 
 fn a_func() -> i32 {
     42
-} 
+}