From b2c9203143781c30f5b1d853ca4ac47b5c02693b Mon Sep 17 00:00:00 2001
From: "Jeremy G. Siek" <jsiek@indiana.edu>
Date: Tue, 2 Mar 2021 12:51:03 -0500
Subject: [PATCH] adding missing exit for pattern variable in wrong context and
 a test case for it (#324)

---
 executable_semantics/BUILD                            |  1 +
 executable_semantics/interpreter/typecheck.cpp        |  1 +
 .../testdata/pattern_variable_fail.6c                 |  8 ++++++++
 .../testdata/pattern_variable_fail.golden             | 11 +++++++++++
 4 files changed, 21 insertions(+)
 create mode 100644 executable_semantics/testdata/pattern_variable_fail.6c
 create mode 100644 executable_semantics/testdata/pattern_variable_fail.golden

diff --git a/executable_semantics/BUILD b/executable_semantics/BUILD
index 72e6a3a4834e..05f4806210ae 100644
--- a/executable_semantics/BUILD
+++ b/executable_semantics/BUILD
@@ -90,6 +90,7 @@ EXAMPLES = [
     "match_type",
     "next",
     "pattern_init",
+    "pattern_variable_fail",
     "record1",
     "struct1",
     "struct2",
diff --git a/executable_semantics/interpreter/typecheck.cpp b/executable_semantics/interpreter/typecheck.cpp
index ad89ea9d442c..d9880d9dc26f 100644
--- a/executable_semantics/interpreter/typecheck.cpp
+++ b/executable_semantics/interpreter/typecheck.cpp
@@ -149,6 +149,7 @@ auto TypeCheckExp(Expression* e, TypeEnv* env, Env* ct_env, Value* expected,
             << ": compilation error, pattern variables are only allowed in "
                "pattern context"
             << std::endl;
+        exit(-1);
       }
       auto t =
           ToType(e->line_num, InterpExp(ct_env, e->u.pattern_variable.type));
diff --git a/executable_semantics/testdata/pattern_variable_fail.6c b/executable_semantics/testdata/pattern_variable_fail.6c
new file mode 100644
index 000000000000..6abbf7b5838e
--- /dev/null
+++ b/executable_semantics/testdata/pattern_variable_fail.6c
@@ -0,0 +1,8 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+fn main() -> Int {
+  Int : x;  // error
+  return 1;
+}
diff --git a/executable_semantics/testdata/pattern_variable_fail.golden b/executable_semantics/testdata/pattern_variable_fail.golden
new file mode 100644
index 000000000000..78b7f53f731d
--- /dev/null
+++ b/executable_semantics/testdata/pattern_variable_fail.golden
@@ -0,0 +1,11 @@
+********** source program **********
+fn main () -> Int {
+Int: x;
+return 1;
+
+}
+********** type checking **********
+--- step exp Int --->
+--- step exp Int --->
+2: compilation error, pattern variables are only allowed in pattern context
+EXIT CODE: 255