Fix `useless_format` suggestions

[rust.git] / tests / ui / format.rs

diff --git a/tests/ui/format.rs b/tests/ui/format.rs
index ac97bd24ea1d93468cc0c4c7e973eea0becf7c5e..e974a4957eaaa0406bd8d14ea44f306993c3ec97 100644 (file)
--- a/tests/ui/format.rs
+++ b/tests/ui/format.rs
@@ -1,6 +1,7 @@
+// run-rustfix
 
-
-#![warn(useless_format)]
+#![allow(clippy::print_literal)]
+#![warn(clippy::useless_format)]
 
 struct Foo(pub String);
 
@@ -12,15 +13,21 @@ fn main() {
     format!("foo");
 
     format!("{}", "foo");
-    format!("{:?}", "foo"); // we only want to warn about `{}`
-    format!("{:+}", "foo"); // we only want to warn about `{}`
+    format!("{:?}", "foo"); // don't warn about debug
+    format!("{:8}", "foo");
+    format!("{:width$}", "foo", width = 8);
+    format!("{:+}", "foo"); // warn when the format makes no difference
+    format!("{:<}", "foo"); // warn when the format makes no difference
     format!("foo {}", "bar");
     format!("{} bar", "foo");
 
     let arg: String = "".to_owned();
     format!("{}", arg);
-    format!("{:?}", arg); // we only want to warn about `{}`
-    format!("{:+}", arg); // we only want to warn about `{}`
+    format!("{:?}", arg); // don't warn about debug
+    format!("{:8}", arg);
+    format!("{:width$}", arg, width = 8);
+    format!("{:+}", arg); // warn when the format makes no difference
+    format!("{:<}", arg); // warn when the format makes no difference
     format!("foo {}", arg);
     format!("{} bar", arg);
 
@@ -40,4 +47,14 @@ fn main() {
 
     // A format! inside a macro should not trigger a warning
     foo!("should not warn");
+
+    // precision on string means slicing without panicking on size:
+    format!("{:.1}", "foo"); // could be "foo"[..1]
+    format!("{:.10}", "foo"); // could not be "foo"[..10]
+    format!("{:.prec$}", "foo", prec = 1);
+    format!("{:.prec$}", "foo", prec = 10);
+
+    format!("{}", 42.to_string());
+    let x = std::path::PathBuf::from("/bar/foo/qux");
+    format!("{}", x.display().to_string());
 }