Update error code number

src/librustc/diagnostics.rs

@@ -1694,12 +1694,12 @@ To understand better how closures work in Rust, read:
 https://doc.rust-lang.org/book/closures.html
 "##,
 
-E0579: r##"
+E0580: r##"
 The `main` function was incorrectly declared.
 
 Erroneous code example:
 
-```compile_fail,E0579
+```compile_fail,E0580
 fn main() -> i32 { // error: main function has wrong type
     0
 }

src/librustc/infer/error_reporting.rs

@@ -631,7 +631,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 struct_span_err!(self.tcx.sess, span, E0317, "{}", failure_str)
             }
             ObligationCauseCode::MainFunctionType => {
-                struct_span_err!(self.tcx.sess, span, E0579, "{}", failure_str)
+                struct_span_err!(self.tcx.sess, span, E0580, "{}", failure_str)
             }
             _ => {
                 struct_span_err!(self.tcx.sess, span, E0308, "{}", failure_str)

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 E0579
+fn main() -> i32 { 0 } //~ ERROR E0580

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 [E0579]
+fn main(x: isize) { } //~ ERROR: main function has wrong type [E0580]

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 [E0579]
+extern fn main() {} //~ ERROR: main function has wrong type [E0580]

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 [E0579]
+//~^ ERROR: main function has wrong type [E0580]
     ' '
 }

src/test/compile-fail/main-wrong-type.rs

@@ -14,5 +14,5 @@ struct S {
 }
 
 fn main(foo: S) {
-//~^ ERROR: main function has wrong type [E0579]
+//~^ ERROR: main function has wrong type [E0580]
 }