diff --git a/src/librustc/diagnostics.rs b/src/librustc/diagnostics.rs
index 0d180e6ad76fda1be666cb41e66e7c0f53bd3083..2878ff5e2846e4f9ad8a776d7758d1a927925e2a 100644
--- a/src/librustc/diagnostics.rs
+++ b/src/librustc/diagnostics.rs
@@ -1694,6 +1694,30 @@ fn main() {
 https://doc.rust-lang.org/book/closures.html
 "##,
 
+E0580: r##"
+The `main` function was incorrectly declared.
+
+Erroneous code example:
+
+```compile_fail,E0580
+fn main() -> i32 { // error: main function has wrong type
+    0
+}
+```
+
+The `main` function prototype should never take arguments or return type.
+Example:
+
+```
+fn main() {
+    // your code
+}
+```
+
+If you want to get command-line arguments, use `std::env::args`. To exit with a
+specified exit code, use `std::process::exit`.
+"##,
+
 }
 
 
diff --git a/src/librustc/infer/error_reporting.rs b/src/librustc/infer/error_reporting.rs
index 095d2a78a94cd993e0b5a0597f07f50006404afc..d859a8b44db0c2af41723e3889427d3042cede3c 100644
--- a/src/librustc/infer/error_reporting.rs
+++ b/src/librustc/infer/error_reporting.rs
@@ -629,10 +629,13 @@ pub fn report_and_explain_type_error(&self,
         let mut diag = match trace.cause.code {
             ObligationCauseCode::IfExpressionWithNoElse => {
                 struct_span_err!(self.tcx.sess, span, E0317, "{}", failure_str)
-            },
+            }
+            ObligationCauseCode::MainFunctionType => {
+                struct_span_err!(self.tcx.sess, span, E0580, "{}", failure_str)
+            }
             _ => {
                 struct_span_err!(self.tcx.sess, span, E0308, "{}", failure_str)
-            },
+            }
         };
         self.note_type_err(&mut diag, &trace.cause, None, Some(trace.values), terr);
         diag
diff --git a/src/test/compile-fail/E0308-3.rs b/src/test/compile-fail/E0580.rs
similarity index 92%
rename from src/test/compile-fail/E0308-3.rs
rename to src/test/compile-fail/E0580.rs
index d7dca056f3fa6ba651766e9a57762b5f84ed0a7d..a2ef7da78a84366ed2a9fcfbbf6ebfdf631909cb 100644
--- a/src/test/compile-fail/E0308-3.rs
+++ b/src/test/compile-fail/E0580.rs
@@ -8,4 +8,4 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn main() -> i32 { 0 } //~ ERROR E0308
+fn main() -> i32 { 0 } //~ ERROR E0580
diff --git a/src/test/compile-fail/bad-main.rs b/src/test/compile-fail/bad-main.rs
index 1253f7569e7e8e48ec2f9e315838d05b5c6940fa..b73b4a6af6e89e8fdcd3e29012ab6000c85ac2bb 100644
--- a/src/test/compile-fail/bad-main.rs
+++ b/src/test/compile-fail/bad-main.rs
@@ -8,4 +8,4 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn main(x: isize) { } //~ ERROR: main function has wrong type
+fn main(x: isize) { } //~ ERROR: main function has wrong type [E0580]
diff --git a/src/test/compile-fail/extern-main-fn.rs b/src/test/compile-fail/extern-main-fn.rs
index 11f299acefa874e55b5efa49b81eb345fd9350be..d9bdb4ecd04777a7384fc3b08c274130a5368f57 100644
--- a/src/test/compile-fail/extern-main-fn.rs
+++ b/src/test/compile-fail/extern-main-fn.rs
@@ -8,4 +8,4 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern fn main() {} //~ ERROR: main function has wrong type
+extern fn main() {} //~ ERROR: main function has wrong type [E0580]
diff --git a/src/test/compile-fail/main-wrong-type-2.rs b/src/test/compile-fail/main-wrong-type-2.rs
index 2878cbc7fc15488d6fcfb865390be929d419f7c9..9d74d1a90493bd8c8f08532c63685824df467c5d 100644
--- a/src/test/compile-fail/main-wrong-type-2.rs
+++ b/src/test/compile-fail/main-wrong-type-2.rs
@@ -9,6 +9,6 @@
 // except according to those terms.
 
 fn main() -> char {
-//~^ ERROR: main function has wrong type
+//~^ ERROR: main function has wrong type [E0580]
     ' '
 }
diff --git a/src/test/compile-fail/main-wrong-type.rs b/src/test/compile-fail/main-wrong-type.rs
index 431b855d5177373cfcabd13a747e6f90dbe86e48..402cd3a2d31b6f2dbeeab22336c924a7361a3d60 100644
--- a/src/test/compile-fail/main-wrong-type.rs
+++ b/src/test/compile-fail/main-wrong-type.rs
@@ -14,5 +14,5 @@ struct S {
 }
 
 fn main(foo: S) {
-//~^ ERROR: main function has wrong type
+//~^ ERROR: main function has wrong type [E0580]
 }