Update E0370 to new error format

src/librustc_typeck/collect.rs

@@ -1164,10 +1164,12 @@ fn convert_enum_def<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
         } else if let Some(disr) = repr_type.disr_incr(tcx, prev_disr) {
             Some(disr)
         } else {
-            span_err!(tcx.sess, v.span, E0370,
-                      "enum discriminant overflowed on value after {}; \
-                       set explicitly via {} = {} if that is desired outcome",
-                      prev_disr.unwrap(), v.node.name, wrapped_disr);
+            struct_span_err!(tcx.sess, v.span, E0370,
+                             "enum discriminant overflowed")
+                .span_label(v.span, &format!("overflowed on value after {}", prev_disr.unwrap()))
+                .note(&format!("explicitly set `{} = {}` if that is desired outcome",
+                               v.node.name, wrapped_disr))
+                .emit();
             None
         }.unwrap_or(wrapped_disr);
         prev_disr = Some(disr);

src/test/compile-fail/discrim-overflow-2.rs

@@ -24,7 +24,9 @@ fn f_i8() {
     enum A {
         Ok = i8::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed on value after 127i8; set explicitly via OhNo = -128i8 if that is desired outcome
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 127i8
+              //~| NOTE explicitly set `OhNo = -128i8` if that is desired outcome
     }
 }
 
@@ -33,7 +35,9 @@ fn f_u8() {
     enum A {
         Ok = u8::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed on value after 255u8; set explicitly via OhNo = 0u8 if that is desired outcome
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 255u8
+              //~| NOTE explicitly set `OhNo = 0u8` if that is desired outcome
     }
 }
 
@@ -42,7 +46,9 @@ fn f_i16() {
     enum A {
         Ok = i16::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 32767i16
+              //~| NOTE explicitly set `OhNo = -32768i16` if that is desired outcome
     }
 }
 
@@ -51,7 +57,9 @@ fn f_u16() {
     enum A {
         Ok = u16::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 65535u16
+              //~| NOTE explicitly set `OhNo = 0u16` if that is desired outcome
     }
 }
 
@@ -60,7 +68,9 @@ fn f_i32() {
     enum A {
         Ok = i32::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 2147483647i32
+              //~| NOTE explicitly set `OhNo = -2147483648i32` if that is desired outcome
     }
 }
 
@@ -69,7 +79,9 @@ fn f_u32() {
     enum A {
         Ok = u32::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 4294967295u32
+              //~| NOTE explicitly set `OhNo = 0u32` if that is desired outcome
     }
 }
 
@@ -78,7 +90,9 @@ fn f_i64() {
     enum A {
         Ok = i64::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 9223372036854775807i64
+              //~| NOTE explicitly set `OhNo = -9223372036854775808i64` if that is desired outcome
     }
 }
 
@@ -87,7 +101,9 @@ fn f_u64() {
     enum A {
         Ok = u64::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 18446744073709551615u64
+              //~| NOTE explicitly set `OhNo = 0u64` if that is desired outcome
     }
 }
 

src/test/compile-fail/discrim-overflow.rs

@@ -22,7 +22,9 @@ fn f_i8() {
     enum A {
         Ok = i8::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed on value after 127i8; set explicitly via OhNo = -128i8 if that is desired outcome
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 127i8
+              //~| NOTE explicitly set `OhNo = -128i8` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -33,7 +35,9 @@ fn f_u8() {
     enum A {
         Ok = u8::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed on value after 255u8; set explicitly via OhNo = 0u8 if that is desired outcome
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 255u8
+              //~| NOTE explicitly set `OhNo = 0u8` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -44,7 +48,9 @@ fn f_i16() {
     enum A {
         Ok = i16::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| NOTE overflowed on value after 32767i16
+              //~| NOTE explicitly set `OhNo = -32768i16` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -55,7 +61,9 @@ fn f_u16() {
     enum A {
         Ok = u16::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 65535u16
+              //~| NOTE explicitly set `OhNo = 0u16` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -66,7 +74,9 @@ fn f_i32() {
     enum A {
         Ok = i32::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 2147483647i32
+              //~| NOTE explicitly set `OhNo = -2147483648i32` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -77,7 +87,9 @@ fn f_u32() {
     enum A {
         Ok = u32::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 4294967295u32
+              //~| NOTE explicitly set `OhNo = 0u32` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -88,7 +100,9 @@ fn f_i64() {
     enum A {
         Ok = i64::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 9223372036854775807i64
+              //~| NOTE explicitly set `OhNo = -9223372036854775808i64` if that is desired outcome
     }
 
     let x = A::Ok;
@@ -99,7 +113,9 @@ fn f_u64() {
     enum A {
         Ok = u64::MAX - 1,
         Ok2,
-        OhNo, //~ ERROR enum discriminant overflowed
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 18446744073709551615u64
+              //~| NOTE explicitly set `OhNo = 0u64` if that is desired outcome
     }
 
     let x = A::Ok;