From cd5362c7bb0b207f484a8dfb8db229fd2bffef09 Mon Sep 17 00:00:00 2001
From: Chris Manghane <cmang@golang.org>
Date: Thu, 20 Aug 2015 10:26:23 -0700
Subject: [PATCH] compiler: Don't crash on invalid arithmetic ops.

The gofrontend would crash after hitting an unreachable state while
trying to determine the type of an arithmetic expression involving
non-numeric values.  Instead of crashing, it should fail gracefully
if the relevant error is already reported.

Fixes golang/go#11537.

Change-Id: I84ec06bb944b8af34ec5e5864a5149c11c782919
Reviewed-on: https://go-review.googlesource.com/13793
Reviewed-by: Ian Lance Taylor <iant@golang.org>
---
 go/expressions.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/go/expressions.cc b/go/expressions.cc
index c9323f562..79b772e20 100644
--- a/go/expressions.cc
+++ b/go/expressions.cc
@@ -15150,7 +15150,11 @@ Numeric_constant::set_type(Type* type, bool issue_error, Location loc)
   else if (type->complex_type() != NULL)
     ret = this->check_complex_type(type->complex_type(), issue_error, loc);
   else
-    go_unreachable();
+    {
+      ret = false;
+      if (issue_error)
+        go_assert(saw_errors());
+    }
   if (ret)
     this->type_ = type;
   return ret;