From de2316bd0c38d1c5961bb038f76715f190495abf Mon Sep 17 00:00:00 2001
From: Richard Smith <richard@metafoo.co.uk>
Date: Mon, 22 Jan 2024 11:32:59 -0800
Subject: [PATCH] Fix crash when `and` or `or` appear outside a function.
 (#3633)

Found by fuzzer.
---
 toolchain/check/handle_operator.cpp           |  4 +-
 .../fail_and_or_not_in_function.carbon        | 66 +++++++++++++++++++
 2 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 toolchain/check/testdata/operators/fail_and_or_not_in_function.carbon

diff --git a/toolchain/check/handle_operator.cpp b/toolchain/check/handle_operator.cpp
index ec1f200c4cbe..fcb930470dc3 100644
--- a/toolchain/check/handle_operator.cpp
+++ b/toolchain/check/handle_operator.cpp
@@ -344,7 +344,7 @@ static auto HandleShortCircuitOperand(Context& context,
   context.inst_block_stack().Pop();
   context.inst_block_stack().Push(end_block_id);
   context.inst_block_stack().Push(rhs_block_id);
-  context.AddCurrentCodeBlockToFunction();
+  context.AddCurrentCodeBlockToFunction(parse_node);
 
   // HandleShortCircuitOperator will follow, and doesn't need the operand on the
   // node stack.
@@ -379,7 +379,7 @@ static auto HandleShortCircuitOperator(Context& context,
   auto resume_block_id = context.inst_block_stack().PeekOrAdd(/*depth=*/1);
   context.AddInst({parse_node, SemIR::BranchWithArg{resume_block_id, rhs_id}});
   context.inst_block_stack().Pop();
-  context.AddCurrentCodeBlockToFunction();
+  context.AddCurrentCodeBlockToFunction(parse_node);
 
   // Collect the result from either the first or second operand.
   context.AddInstAndPush(
diff --git a/toolchain/check/testdata/operators/fail_and_or_not_in_function.carbon b/toolchain/check/testdata/operators/fail_and_or_not_in_function.carbon
new file mode 100644
index 000000000000..f0b05f8f2e62
--- /dev/null
+++ b/toolchain/check/testdata/operators/fail_and_or_not_in_function.carbon
@@ -0,0 +1,66 @@
+// 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
+//
+// AUTOUPDATE
+
+// TODO: Make this a compile-time function.
+fn F(b: bool) -> type {
+  return if b then i32 else f64;
+}
+
+// TODO: Short-circuit operators should be permitted outside functions.
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+9]]:11: ERROR: Cannot evaluate type expression.
+// CHECK:STDERR: var and_: F(true and true);
+// CHECK:STDERR:           ^~~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+6]]:13: ERROR: Semantics TODO: `Control flow expressions are currently only supported inside functions.`.
+// CHECK:STDERR: var and_: F(true and true);
+// CHECK:STDERR:             ^~~~~~~~
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+3]]:13: ERROR: Semantics TODO: `Control flow expressions are currently only supported inside functions.`.
+// CHECK:STDERR: var and_: F(true and true);
+// CHECK:STDERR:             ^~~~~~~~~~~~~
+var and_: F(true and true);
+
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+9]]:10: ERROR: Cannot evaluate type expression.
+// CHECK:STDERR: var or_: F(true or true);
+// CHECK:STDERR:          ^~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+6]]:12: ERROR: Semantics TODO: `Control flow expressions are currently only supported inside functions.`.
+// CHECK:STDERR: var or_: F(true or true);
+// CHECK:STDERR:            ^~~~~~~
+// CHECK:STDERR: fail_and_or_not_in_function.carbon:[[@LINE+3]]:12: ERROR: Semantics TODO: `Control flow expressions are currently only supported inside functions.`.
+// CHECK:STDERR: var or_: F(true or true);
+// CHECK:STDERR:            ^~~~~~~~~~~~
+var or_: F(true or true);
+
+// CHECK:STDOUT: --- fail_and_or_not_in_function.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %.1: bool = bool_literal true [template]
+// CHECK:STDOUT:   %.2: bool = bool_literal false [template]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   %.loc33_17: bool = block_arg <unexpected instblockref block13>
+// CHECK:STDOUT:   %.loc33_11.1: init type = call <unexpected instref inst+27>(%.loc33_17)
+// CHECK:STDOUT:   %.loc33_24: type = value_of_initializer %.loc33_11.1
+// CHECK:STDOUT:   %.loc33_11.2: type = converted %.loc33_11.1, %.loc33_24
+// CHECK:STDOUT:   %or_.var: ref <error> = var or_
+// CHECK:STDOUT:   %or_: ref <error> = bind_name or_, %or_.var
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @F(%b: bool) -> type {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   %b.ref: bool = name_ref b, %b
+// CHECK:STDOUT:   if %b.ref br !if.expr.then else br !if.expr.else
+// CHECK:STDOUT:
+// CHECK:STDOUT: !if.expr.then:
+// CHECK:STDOUT:   br !if.expr.result(i32)
+// CHECK:STDOUT:
+// CHECK:STDOUT: !if.expr.else:
+// CHECK:STDOUT:   br !if.expr.result(f64)
+// CHECK:STDOUT:
+// CHECK:STDOUT: !if.expr.result:
+// CHECK:STDOUT:   %.loc9: type = block_arg !if.expr.result
+// CHECK:STDOUT:   return %.loc9
+// CHECK:STDOUT: }
+// CHECK:STDOUT: