Vulkan: SPIR-V Gen: Fix crash in array of struct constant

Bug: chromium:1260690
Change-Id: I51fe85a2ebc23c3fcaa3c961c4ebf84688bbed31
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3226309
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>

src/compiler/translator/OutputSPIRV.cpp

@@ -4835,8 +4835,10 @@ void OutputSPIRVTraverser::visitConstantUnion(TIntermConstantUnion *node)
         //   constructed.
         if (parentAggregate->isConstructor())
         {
-            const TStructure *structure = parentAggregate->getType().getStruct();
-            if (structure != nullptr)
+            const TType &parentType     = parentAggregate->getType();
+            const TStructure *structure = parentType.getStruct();
+
+            if (structure != nullptr && !parentType.isArray())
             {
                 expectedBasicType = structure->fields()[childIndex]->type()->getBasicType();
             }

src/tests/gl_tests/GLSLTest.cpp

@@ -14198,6 +14198,30 @@ void main()
     ASSERT_GL_NO_ERROR();
 }
 
+// Regression test for a crash in SPIR-V output when faced with an array of struct constant.
+TEST_P(GLSLTest_ES3, ArrayOfStructConstantBug)
+{
+    constexpr char kFS[] = R"(#version 300 es
+struct S {
+    int foo;
+};
+void main() {
+    S a[3];
+    a = S[3](S(0), S(1), S(2));
+})";
+
+    GLuint shader = glCreateShader(GL_FRAGMENT_SHADER);
+
+    const char *sourceArray[1] = {kFS};
+    GLint lengths[1]           = {static_cast<GLint>(sizeof(kFS) - 1)};
+    glShaderSource(shader, 1, sourceArray, lengths);
+    glCompileShader(shader);
+
+    GLint compileResult;
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &compileResult);
+    EXPECT_NE(compileResult, 0);
+}
+
 }  // anonymous namespace
 
 ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND(GLSLTest, WithGlslang(ES2_VULKAN()));