resolver: Check IsStorable() earlier for array els

This was done in ValidateArray(), but this comes after the call to DefaultAlignAndSize(), which will ICE if the type is not storable.

Change-Id: Ia3f1b640f42a45362487c3156237b59ea6fed68b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/53043
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>

src/resolver/resolver.cc

diff --git a/src/resolver/resolver.cc b/src/resolver/resolver.cc
index d94008a..2ac42f9 100644
--- a/src/resolver/resolver.cc
+++ b/src/resolver/resolver.cc
@@ -2653,6 +2653,14 @@
     return nullptr;
   }
 
+  if (!IsStorable(el_ty)) {  // Check must come before DefaultAlignAndSize()
+    builder_->Diagnostics().add_error(
+        el_ty->FriendlyName(builder_->Symbols()) +
+            " cannot be used as an element type of an array",
+        source);
+    return nullptr;
+  }
+
   uint32_t el_align = 0;
   uint32_t el_size = 0;
   if (!DefaultAlignAndSize(el_ty, el_align, el_size)) {
@@ -2702,14 +2710,6 @@
 bool Resolver::ValidateArray(const sem::Array* arr, const Source& source) {
   auto* el_ty = arr->ElemType();
 
-  if (!IsStorable(el_ty)) {
-    builder_->Diagnostics().add_error(
-        el_ty->FriendlyName(builder_->Symbols()) +
-            " cannot be used as an element type of an array",
-        source);
-    return false;
-  }
-
   if (auto* el_str = el_ty->As<sem::Struct>()) {
     if (el_str->IsBlockDecorated()) {
       // https://gpuweb.github.io/gpuweb/wgsl/#attributes

src/resolver/type_validation_test.cc

diff --git a/src/resolver/type_validation_test.cc b/src/resolver/type_validation_test.cc
index e45db09..38375f8 100644
--- a/src/resolver/type_validation_test.cc
+++ b/src/resolver/type_validation_test.cc
@@ -353,6 +353,17 @@
   EXPECT_TRUE(r()->Resolve()) << r()->error();
 }
 
+TEST_F(ResolverTypeValidationTest, ArrayOfNonStorableType) {
+  auto* tex_ty = ty.sampled_texture(ast::TextureDimension::k2d, ty.f32());
+  Global("arr", ty.array(Source{{12, 34}}, tex_ty, 4),
+         ast::StorageClass::kPrivate);
+
+  EXPECT_FALSE(r()->Resolve());
+  EXPECT_EQ(r()->error(),
+            "12:34 error: texture_2d<f32> cannot be used as an element type of "
+            "an array");
+}
+
 namespace GetCanonicalTests {
 struct Params {
   create_ast_type_func_ptr create_ast_type;