[wgsl-reader] Adding body_statement to statement grammar

Block statements will now be parsed in ParserImpl::statement()

Change-Id: I28f63d4a53c85c0306c57df545f78b4562c6ea7b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/27262
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: dan sinclair <dsinclair@chromium.org>

src/reader/wgsl/parser_impl.cc

@@ -1479,6 +1479,7 @@ std::unique_ptr<ast::BlockStatement> ParserImpl::statements() {
 //   | continue_stmt SEMICOLON
 //   | DISCARD SEMICOLON
 //   | assignment_stmt SEMICOLON
+//   | body_stmt
 std::unique_ptr<ast::Statement> ParserImpl::statement() {
   auto t = peek();
   if (t.IsSemicolon()) {
@@ -1588,6 +1589,12 @@ std::unique_ptr<ast::Statement> ParserImpl::statement() {
     return assign;
   }
 
+  auto body = body_stmt();
+  if (has_error())
+    return nullptr;
+  if (body != nullptr)
+    return body;
+
   return nullptr;
 }
 

src/reader/wgsl/parser_impl_statement_test.cc

@@ -221,6 +221,23 @@ TEST_F(ParserImplTest, Statement_Discard_MissingSemicolon) {
   EXPECT_EQ(p->error(), "1:8: missing ;");
 }
 
+TEST_F(ParserImplTest, Statement_Body) {
+  auto* p = parser("{ var i: i32; }");
+  auto e = p->statement();
+  ASSERT_FALSE(p->has_error()) << p->error();
+  ASSERT_NE(e, nullptr);
+  ASSERT_TRUE(e->IsBlock());
+  EXPECT_TRUE(e->AsBlock()->get(0)->IsVariableDecl());
+}
+
+TEST_F(ParserImplTest, Statement_Body_Invalid) {
+  auto* p = parser("{ fn main() -> {}}");
+  auto e = p->statement();
+  ASSERT_TRUE(p->has_error());
+  ASSERT_EQ(e, nullptr);
+  EXPECT_EQ(p->error(), "1:3: missing }");
+}
+
 }  // namespace
 }  // namespace wgsl
 }  // namespace reader