diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f4ef8b337c..d58e85e038 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -222,6 +222,7 @@ set(TINT_TEST_SRCS
   ast/kill_statement_test.cc
   ast/location_decoration_test.cc
   ast/loop_statement_test.cc
+  ast/member_accessor_expression_test.cc
   ast/module_test.cc
   ast/set_decoration_test.cc
   ast/struct_member_test.cc
diff --git a/src/ast/loop_statement.cc b/src/ast/loop_statement.cc
index e99c87cc5e..97efc069d0 100644
--- a/src/ast/loop_statement.cc
+++ b/src/ast/loop_statement.cc
@@ -54,10 +54,10 @@ void LoopStatement::to_str(std::ostream& out, size_t indent) const {
   if (continuing_.size() > 0) {
     make_indent(out, indent + 2);
     out << "continuing {" << std::endl;
-  
+
     for (const auto& stmt : continuing_)
       stmt->to_str(out, indent + 4);
-  
+
     make_indent(out, indent + 2);
     out << "}" << std::endl;
   }
diff --git a/src/ast/loop_statement_test.cc b/src/ast/loop_statement_test.cc
index cb7f8cbcd6..d49636fca6 100644
--- a/src/ast/loop_statement_test.cc
+++ b/src/ast/loop_statement_test.cc
@@ -17,8 +17,8 @@
 #include <sstream>
 
 #include "gtest/gtest.h"
-#include "src/ast/kill_statement.h"
 #include "src/ast/if_statement.h"
+#include "src/ast/kill_statement.h"
 #include "src/ast/nop_statement.h"
 
 namespace tint {
diff --git a/src/ast/member_accessor_expression.cc b/src/ast/member_accessor_expression.cc
index 24f43ba29f..180b06b9e4 100644
--- a/src/ast/member_accessor_expression.cc
+++ b/src/ast/member_accessor_expression.cc
@@ -17,6 +17,8 @@
 namespace tint {
 namespace ast {
 
+MemberAccessorExpression::MemberAccessorExpression() = default;
+
 MemberAccessorExpression::MemberAccessorExpression(
     std::unique_ptr<Expression> structure,
     std::unique_ptr<IdentifierExpression> member)
@@ -33,7 +35,13 @@ MemberAccessorExpression::MemberAccessorExpression(
 MemberAccessorExpression::~MemberAccessorExpression() = default;
 
 bool MemberAccessorExpression::IsValid() const {
-  return struct_ != nullptr && member_ != nullptr;
+  if (struct_ == nullptr || !struct_->IsValid()) {
+    return false;
+  }
+  if (member_ == nullptr || !member_->IsValid()) {
+    return false;
+  }
+  return true;
 }
 
 void MemberAccessorExpression::to_str(std::ostream& out, size_t indent) const {
diff --git a/src/ast/member_accessor_expression.h b/src/ast/member_accessor_expression.h
index ff24bad242..996e3ae127 100644
--- a/src/ast/member_accessor_expression.h
+++ b/src/ast/member_accessor_expression.h
@@ -29,6 +29,8 @@ namespace ast {
 /// A member accessor expression
 class MemberAccessorExpression : public Expression {
  public:
+  /// Constructor
+  MemberAccessorExpression();
   /// Constructor
   /// @param structure the structure
   /// @param member the member
diff --git a/src/ast/member_accessor_expression_test.cc b/src/ast/member_accessor_expression_test.cc
new file mode 100644
index 0000000000..57e30be342
--- /dev/null
+++ b/src/ast/member_accessor_expression_test.cc
@@ -0,0 +1,109 @@
+// 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/ast/member_accessor_expression.h"
+
+#include <sstream>
+
+#include "gtest/gtest.h"
+#include "src/ast/identifier_expression.h"
+
+namespace tint {
+namespace ast {
+
+using MemberAccessorExpressionTest = testing::Test;
+
+TEST_F(MemberAccessorExpressionTest, Creation) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  auto str_ptr = str.get();
+  auto mem_ptr = mem.get();
+
+  MemberAccessorExpression stmt(std::move(str), std::move(mem));
+  EXPECT_EQ(stmt.structure(), str_ptr);
+  EXPECT_EQ(stmt.member(), mem_ptr);
+}
+
+TEST_F(MemberAccessorExpressionTest, Creation_WithSource) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  MemberAccessorExpression stmt(Source{20, 2}, std::move(str), std::move(mem));
+  auto src = stmt.source();
+  EXPECT_EQ(src.line, 20);
+  EXPECT_EQ(src.column, 2);
+}
+
+TEST_F(MemberAccessorExpressionTest, IsMemberAccessor) {
+  MemberAccessorExpression stmt;
+  EXPECT_TRUE(stmt.IsMemberAccessor());
+}
+
+TEST_F(MemberAccessorExpressionTest, IsValid) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  MemberAccessorExpression stmt(std::move(str), std::move(mem));
+  EXPECT_TRUE(stmt.IsValid());
+}
+
+TEST_F(MemberAccessorExpressionTest, IsValid_NullStruct) {
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  MemberAccessorExpression stmt;
+  stmt.set_member(std::move(mem));
+  EXPECT_FALSE(stmt.IsValid());
+}
+
+TEST_F(MemberAccessorExpressionTest, IsValid_InvalidStruct) {
+  auto str = std::make_unique<IdentifierExpression>("");
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  MemberAccessorExpression stmt(std::move(str), std::move(mem));
+  EXPECT_FALSE(stmt.IsValid());
+}
+
+TEST_F(MemberAccessorExpressionTest, IsValid_NullMember) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+
+  MemberAccessorExpression stmt;
+  stmt.set_structure(std::move(str));
+  EXPECT_FALSE(stmt.IsValid());
+}
+
+TEST_F(MemberAccessorExpressionTest, IsValid_InvalidMember) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+  auto mem = std::make_unique<IdentifierExpression>("");
+
+  MemberAccessorExpression stmt(std::move(str), std::move(mem));
+  EXPECT_FALSE(stmt.IsValid());
+}
+
+TEST_F(MemberAccessorExpressionTest, ToStr) {
+  auto str = std::make_unique<IdentifierExpression>("structure");
+  auto mem = std::make_unique<IdentifierExpression>("member");
+
+  MemberAccessorExpression stmt(std::move(str), std::move(mem));
+  std::ostringstream out;
+  stmt.to_str(out, 2);
+  EXPECT_EQ(out.str(), R"(  MemberAccessor{
+    Identifier{structure}
+    Identifier{member}
+  }
+)");
+}
+
+}  // namespace ast
+}  // namespace tint