check for write macro and write_fmt with err msg

added ui test
blessed stderrs
fixed typo
reblessed

2 files changed, 76 insertions, 0 deletions

diff --git a/tests/ui/macros/missing-writer.rs b/tests/ui/macros/missing-writer.rs
new file mode 100644
index 00000000000..7df965c3684
--- /dev/null
+++ b/tests/ui/macros/missing-writer.rs
@@ -0,0 +1,17 @@
+// Check error for missing writer in writeln! and write! macro
+fn main() {
+    let x = 1;
+    let y = 2;
+    write!("{}_{}", x, y);
+    //~^ ERROR format argument must be a string literal
+    //~| HELP you might be missing a string literal to format with
+    //~| ERROR cannot write into `&'static str`
+    //~| NOTE must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
+    //~| HELP a writer is needed before this format string
+    writeln!("{}_{}", x, y);
+    //~^ ERROR format argument must be a string literal
+    //~| HELP you might be missing a string literal to format with
+    //~| ERROR cannot write into `&'static str`
+    //~| NOTE must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
+    //~| HELP a writer is needed before this format string
+}
diff --git a/tests/ui/macros/missing-writer.stderr b/tests/ui/macros/missing-writer.stderr
new file mode 100644
index 00000000000..86dfe7d65ea
--- /dev/null
+++ b/tests/ui/macros/missing-writer.stderr
@@ -0,0 +1,59 @@
+error: format argument must be a string literal
+  --> $DIR/missing-writer.rs:5:21
+   |
+LL |     write!("{}_{}", x, y);
+   |                     ^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     write!("{}_{}", "{} {}", x, y);
+   |                     ++++++++
+
+error: format argument must be a string literal
+  --> $DIR/missing-writer.rs:11:23
+   |
+LL |     writeln!("{}_{}", x, y);
+   |                       ^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     writeln!("{}_{}", "{} {}", x, y);
+   |                       ++++++++
+
+error[E0599]: cannot write into `&'static str`
+  --> $DIR/missing-writer.rs:5:12
+   |
+LL |     write!("{}_{}", x, y);
+   |     -------^^^^^^^------- method not found in `&str`
+   |
+note: must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
+  --> $DIR/missing-writer.rs:5:12
+   |
+LL |     write!("{}_{}", x, y);
+   |            ^^^^^^^
+help: a writer is needed before this format string
+  --> $DIR/missing-writer.rs:5:12
+   |
+LL |     write!("{}_{}", x, y);
+   |            ^
+
+error[E0599]: cannot write into `&'static str`
+  --> $DIR/missing-writer.rs:11:14
+   |
+LL |     writeln!("{}_{}", x, y);
+   |     ---------^^^^^^^------- method not found in `&str`
+   |
+note: must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
+  --> $DIR/missing-writer.rs:11:14
+   |
+LL |     writeln!("{}_{}", x, y);
+   |              ^^^^^^^
+help: a writer is needed before this format string
+  --> $DIR/missing-writer.rs:11:14
+   |
+LL |     writeln!("{}_{}", x, y);
+   |              ^
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0599`.