From 58bd8786e891f69fcb7982938a635d4f8b16496b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Wed, 31 Jul 2019 14:10:33 -0700
Subject: [PATCH] Do not lint on SizeOverflow, always error

---
 src/librustc/mir/interpret/error.rs   | 4 +++-
 src/test/ui/consts/issue-55878.stderr | 5 ++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index 7c1941196390a..acdabd1e53d63 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -137,16 +137,18 @@ impl<'tcx> ConstEvalErr<'tcx> {
         message: &str,
         lint_root: Option<hir::HirId>,
     ) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
+        let mut must_error = false;
         match self.error {
             err_inval!(Layout(LayoutError::Unknown(_))) |
             err_inval!(TooGeneric) =>
                 return Err(ErrorHandled::TooGeneric),
             err_inval!(TypeckError) =>
                 return Err(ErrorHandled::Reported),
+            err_inval!(LayoutError::SizeOverflow(_)) => must_error = true,
             _ => {},
         }
         trace!("reporting const eval failure at {:?}", self.span);
-        let mut err = if let Some(lint_root) = lint_root {
+        let mut err = if let (Some(lint_root), false) = (lint_root, must_error) {
             let hir_id = self.stacktrace
                 .iter()
                 .rev()
diff --git a/src/test/ui/consts/issue-55878.stderr b/src/test/ui/consts/issue-55878.stderr
index 03537ff20bf5e..7ca7024912fbb 100644
--- a/src/test/ui/consts/issue-55878.stderr
+++ b/src/test/ui/consts/issue-55878.stderr
@@ -1,4 +1,4 @@
-error: reaching this expression at runtime will panic or abort
+error[E0080]: reaching this expression at runtime will panic or abort
   --> $SRC_DIR/libcore/mem/mod.rs:LL:COL
    |
 LL |     intrinsics::size_of::<T>()
@@ -8,8 +8,7 @@ LL |     intrinsics::size_of::<T>()
    |
 LL |     println!("Size: {}", std::mem::size_of::<[u8; std::u64::MAX as usize]>());
    |                          ---------------------------------------------------
-   |
-   = note: `#[deny(const_err)]` on by default
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0080`.