make simple check of prinf function.

With this commit we start to make some simple
check when the name resolution fails, and
we generate some helper message in case the
name is a C name like in the case of the `printf`
and suggest the correct rust method.

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/src/test/ui/suggestions/seggest_print_over_printf.rs b/src/test/ui/suggestions/seggest_print_over_printf.rs
new file mode 100644
index 00000000000..25566cd7f2a
--- /dev/null
+++ b/src/test/ui/suggestions/seggest_print_over_printf.rs
@@ -0,0 +1,9 @@
+// Suggest to a user to use the print macros
+// instead to use the printf.
+
+fn main() {
+    let x = 4;
+    printf("%d", x);
+    //~^ ERROR cannot find function `printf` in this scope
+    //~| HELP you may have meant to use the `print` macro
+}
diff --git a/src/test/ui/suggestions/seggest_print_over_printf.stderr b/src/test/ui/suggestions/seggest_print_over_printf.stderr
new file mode 100644
index 00000000000..7b1ce047a92
--- /dev/null
+++ b/src/test/ui/suggestions/seggest_print_over_printf.stderr
@@ -0,0 +1,14 @@
+error[E0425]: cannot find function `printf` in this scope
+  --> $DIR/seggest_print_over_printf.rs:6:5
+   |
+LL |     printf("%d", x);
+   |     ^^^^^^ not found in this scope
+   |
+help: you may have meant to use the `print` macro
+   |
+LL |     print!("%d", x);
+   |     ~~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0425`.