avoid mutable state and override main message

Author: estebank

src/librustc/mir/interpret/error.rs

@@ -137,16 +137,15 @@ impl<'tcx> ConstEvalErr<'tcx> {
         message: &str,
         lint_root: Option<hir::HirId>,
     ) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
-        let mut must_error = false;
-        match self.error {
+        let must_error = match self.error {
             err_inval!(Layout(LayoutError::Unknown(_))) |
             err_inval!(TooGeneric) =>
                 return Err(ErrorHandled::TooGeneric),
             err_inval!(TypeckError) =>
                 return Err(ErrorHandled::Reported),
-            err_inval!(Layout(LayoutError::SizeOverflow(_))) => must_error = true,
-            _ => {},
-        }
+            err_inval!(Layout(LayoutError::SizeOverflow(_))) => true,
+            _ => false,
+        };
         trace!("reporting const eval failure at {:?}", self.span);
         let mut err = if let (Some(lint_root), false) = (lint_root, must_error) {
             let hir_id = self.stacktrace
@@ -161,6 +160,8 @@ impl<'tcx> ConstEvalErr<'tcx> {
                 tcx.span,
                 message,
             )
+        } else if must_error {
+            struct_error(tcx, &self.error.to_string())
         } else {
             struct_error(tcx, message)
         };

src/test/ui/consts/issue-55878.rs

@@ -1,4 +1,4 @@
-// error-pattern: reaching this expression at runtime will panic or abort
+// error-pattern: the type `[u8; 18446744073709551615]` is too big for the current architecture
 fn main() {
     println!("Size: {}", std::mem::size_of::<[u8; std::u64::MAX as usize]>());
 }

src/test/ui/consts/issue-55878.stderr

@@ -1,4 +1,4 @@
-error[E0080]: reaching this expression at runtime will panic or abort
+error[E0080]: the type `[u8; 18446744073709551615]` is too big for the current architecture
   --> $SRC_DIR/libcore/mem/mod.rs:LL:COL
    |
 LL |     intrinsics::size_of::<T>()

src/test/ui/issues/issue-56762.rs

@@ -17,8 +17,8 @@ impl TooBigArray {
 }
 
 static MY_TOO_BIG_ARRAY_1: TooBigArray = TooBigArray::new();
-//~^ ERROR could not evaluate static initializer
+//~^ ERROR the type `[u8; 2305843009213693951]` is too big for the current architecture
 static MY_TOO_BIG_ARRAY_2: [u8; HUGE_SIZE] = [0x00; HUGE_SIZE];
-//~^ ERROR could not evaluate static initializer
+//~^ ERROR the type `[u8; 2305843009213693951]` is too big for the current architecture
 
 fn main() { }

src/test/ui/issues/issue-56762.stderr

@@ -1,10 +1,10 @@
-error[E0080]: could not evaluate static initializer
+error[E0080]: the type `[u8; 2305843009213693951]` is too big for the current architecture
   --> $DIR/issue-56762.rs:19:1
    |
 LL | static MY_TOO_BIG_ARRAY_1: TooBigArray = TooBigArray::new();
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[u8; 2305843009213693951]` is too big for the current architecture
 
-error[E0080]: could not evaluate static initializer
+error[E0080]: the type `[u8; 2305843009213693951]` is too big for the current architecture
   --> $DIR/issue-56762.rs:21:1
    |
 LL | static MY_TOO_BIG_ARRAY_2: [u8; HUGE_SIZE] = [0x00; HUGE_SIZE];