diff --git a/BUILD.gn b/BUILD.gn
index 7462bef..0318b62 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -742,6 +742,7 @@
     "src/scope_stack_test.cc",
     "src/type_determiner_test.cc",
     "src/type_manager_test.cc",
+    "src/validator_control_block_test.cc",
     "src/validator_function_test.cc",
     "src/validator_test.cc",
   ]
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 3d82ef6..0a2fa9b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -352,8 +352,9 @@
   scope_stack_test.cc
   type_determiner_test.cc
   type_manager_test.cc
-  validator_test.cc
+  validator_control_block_test.cc
   validator_function_test.cc
+  validator_test.cc
 )
 
 ## Tint library
diff --git a/src/validator_control_block_test.cc b/src/validator_control_block_test.cc
new file mode 100644
index 0000000..60f40e2
--- /dev/null
+++ b/src/validator_control_block_test.cc
@@ -0,0 +1,300 @@
+// Copyright 2020 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/validator_impl.h"
+
+#include "gtest/gtest.h"
+#include "spirv/unified1/GLSL.std.450.h"
+#include "src/ast/case_statement.h"
+#include "src/ast/fallthrough_statement.h"
+#include "src/ast/return_statement.h"
+#include "src/ast/scalar_constructor_expression.h"
+#include "src/ast/sint_literal.h"
+#include "src/ast/switch_statement.h"
+#include "src/ast/type/f32_type.h"
+#include "src/ast/type/i32_type.h"
+#include "src/ast/type/u32_type.h"
+#include "src/ast/uint_literal.h"
+#include "src/ast/variable.h"
+#include "src/ast/variable_decl_statement.h"
+#include "src/type_determiner.h"
+#include "src/validator_test_helper.h"
+
+namespace tint {
+namespace {
+
+class ValidateControlBlockTest : public ValidatorTestHelper,
+                                 public testing::Test {};
+
+TEST_F(ValidateControlBlockTest,
+       DISABLED_SwitchSelectorExpressionNoneIntegerType_Fail) {
+  // var a : f32 = 3.14;
+  // switch (a) {
+  //   default: {}
+  // }
+  ast::type::F32Type f32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &f32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&f32, 3.14f)));
+
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+  ast::CaseSelectorList default_csl;
+  auto block_default = std::make_unique<ast::BlockStatement>();
+  ast::CaseStatementList body;
+  body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(default_csl), std::move(block_default)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(std::make_unique<ast::SwitchStatement>(
+      Source{12, 34}, std::move(cond), std::move(body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(v()->error(),
+            "12:34: v-switch01: switch statement selector expression must be "
+            "of a scalar integer type");
+}
+
+TEST_F(ValidateControlBlockTest, DISABLED_SwitchWithoutDefault_Fail) {
+  // var a : i32 = 2;
+  // switch (a) {
+  //   case 1: {}
+  // }
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &i32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&i32, 2)));
+
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+  ast::CaseSelectorList csl;
+  csl.push_back(std::make_unique<ast::SintLiteral>(&i32, 1));
+  ast::CaseStatementList body;
+  body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(csl), std::make_unique<ast::BlockStatement>()));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(std::make_unique<ast::SwitchStatement>(
+      Source{12, 34}, std::move(cond), std::move(body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(v()->error(),
+            "12:34: v-switch02: switch statement must have exactly one default "
+            "clause");
+}
+
+TEST_F(ValidateControlBlockTest, DISABLED_SwitchWithTwoDefault_Fail) {
+  // var a : i32 = 2;
+  // switch (a) {
+  //   default: {}
+  //   case 1: {}
+  //   default: {}
+  // }
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &i32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&i32, 2)));
+
+  ast::CaseStatementList switch_body;
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+
+  ast::CaseSelectorList default_csl_1;
+  auto block_default_1 = std::make_unique<ast::BlockStatement>();
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(default_csl_1), std::move(block_default_1)));
+
+  ast::CaseSelectorList csl_case_1;
+  csl_case_1.push_back(std::make_unique<ast::SintLiteral>(&i32, 1));
+  auto block_case_1 = std::make_unique<ast::BlockStatement>();
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(csl_case_1), std::move(block_case_1)));
+
+  ast::CaseSelectorList default_csl_2;
+  auto block_default_2 = std::make_unique<ast::BlockStatement>();
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      Source{12, 34}, std::move(default_csl_2), std::move(block_default_2)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(std::make_unique<ast::SwitchStatement>(std::move(cond),
+                                                       std::move(switch_body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(v()->error(),
+            "12:34: v-switch02: switch statement must have exactly one default "
+            "clause");
+}
+
+TEST_F(ValidateControlBlockTest,
+       DISABLED_SwitchConditionTypeMustMatchSelectorType_Fail) {
+  // var a : u32 = 2;
+  // switch (a) {
+  //   case -1: {}
+  //   default: {}
+  // }
+  ast::type::U32Type u32;
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &u32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::UintLiteral>(&u32, 2)));
+
+  ast::CaseStatementList switch_body;
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+
+  ast::CaseSelectorList csl;
+  csl.push_back(std::make_unique<ast::SintLiteral>(&i32, -1));
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      Source{12, 34}, std::move(csl), std::make_unique<ast::BlockStatement>()));
+
+  ast::CaseSelectorList default_csl;
+  auto block_default = std::make_unique<ast::BlockStatement>();
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(default_csl), std::move(block_default)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(std::make_unique<ast::SwitchStatement>(std::move(cond),
+                                                       std::move(switch_body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(
+      v()->error(),
+      "12:34: v-switch03: the case selector values must have the same type "
+      "as the selector expression.");
+}
+
+TEST_F(ValidateControlBlockTest,
+       DISABLED_NonUniqueCaseSelectorLiteralValue_Fail) {
+  // var a : i32 = 2;
+  // switch (a) {
+  //   case 10: {}
+  //   case 0,1,2,10: {}
+  //   default: {}
+  // }
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &i32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&i32, 2)));
+
+  ast::CaseStatementList switch_body;
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+
+  ast::CaseSelectorList csl_1;
+  csl_1.push_back(std::make_unique<ast::SintLiteral>(&i32, 10));
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(csl_1), std::make_unique<ast::BlockStatement>()));
+
+  ast::CaseSelectorList csl_2;
+  csl_2.push_back(std::make_unique<ast::SintLiteral>(&i32, 0));
+  csl_2.push_back(std::make_unique<ast::SintLiteral>(&i32, 1));
+  csl_2.push_back(std::make_unique<ast::SintLiteral>(&i32, 2));
+  csl_2.push_back(std::make_unique<ast::SintLiteral>(&i32, 10));
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      Source{12, 34}, std::move(csl_1),
+      std::make_unique<ast::BlockStatement>()));
+
+  ast::CaseSelectorList default_csl;
+  auto block_default = std::make_unique<ast::BlockStatement>();
+  switch_body.push_back(std::make_unique<ast::CaseStatement>(
+      std::move(default_csl), std::move(block_default)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(std::make_unique<ast::SwitchStatement>(std::move(cond),
+                                                       std::move(switch_body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(
+      v()->error(),
+      "12:34: v-switch04: a literal value must not appear more than once in "
+      "the case selectors for a switch statement");
+}
+
+TEST_F(ValidateControlBlockTest,
+       DISABLED_LastClauseLastStatementIsFallthrough_Fail) {
+  // var a : i32 = 2;
+  // switch (a) {
+  //   default: { fallthrough; }
+  // }
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &i32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&i32, 2)));
+
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+  ast::CaseSelectorList default_csl;
+  auto block_default = std::make_unique<ast::BlockStatement>();
+  block_default->append(std::make_unique<ast::FallthroughStatement>());
+  ast::CaseStatementList body;
+  body.push_back(std::make_unique<ast::CaseStatement>(
+      Source{12, 34}, std::move(default_csl), std::move(block_default)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(
+      std::make_unique<ast::SwitchStatement>(std::move(cond), std::move(body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_FALSE(v()->ValidateStatements(block.get()));
+  EXPECT_EQ(v()->error(),
+            "12:34: v-switch05: a fallthrough statement must not appear as the "
+            "last statement in last clause of a switch");
+}
+
+TEST_F(ValidateControlBlockTest, SwitchCase_Pass) {
+  // var a : i32 = 2;
+  // switch (a) {
+  //   default: {}
+  //   case 5: {}
+  // }
+  ast::type::I32Type i32;
+  auto var =
+      std::make_unique<ast::Variable>("a", ast::StorageClass::kNone, &i32);
+  var->set_constructor(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::SintLiteral>(&i32, 2)));
+
+  auto cond = std::make_unique<ast::IdentifierExpression>("a");
+  ast::CaseSelectorList default_csl;
+  auto block_default = std::make_unique<ast::BlockStatement>();
+  ast::CaseStatementList body;
+  body.push_back(std::make_unique<ast::CaseStatement>(
+      Source{12, 34}, std::move(default_csl), std::move(block_default)));
+  ast::CaseSelectorList case_csl;
+  case_csl.push_back(std::make_unique<ast::SintLiteral>(&i32, 5));
+  auto block_case = std::make_unique<ast::BlockStatement>();
+  body.push_back(std::make_unique<ast::CaseStatement>(std::move(case_csl),
+                                                      std::move(block_case)));
+
+  auto block = std::make_unique<ast::BlockStatement>();
+  block->append(std::make_unique<ast::VariableDeclStatement>(std::move(var)));
+  block->append(
+      std::make_unique<ast::SwitchStatement>(std::move(cond), std::move(body)));
+
+  EXPECT_TRUE(td()->DetermineStatements(block.get())) << td()->error();
+  EXPECT_TRUE(v()->ValidateStatements(block.get())) << v()->error();
+}
+
+}  // namespace
+}  // namespace tint