diff --git a/src/writer/spirv/builder.cc b/src/writer/spirv/builder.cc
index 8011e74..802e34a 100644
--- a/src/writer/spirv/builder.cc
+++ b/src/writer/spirv/builder.cc
@@ -680,6 +680,9 @@
         }
         constructor_is_const = false;
       }
+    }
+
+    for (const auto& e : init->values()) {
       uint32_t id = 0;
       if (constructor_is_const) {
         id = GenerateConstructorExpression(e->AsConstructor(), is_global_init);
@@ -691,8 +694,32 @@
         return 0;
       }
 
-      out << "_" << id;
-      ops.push_back(Operand::Int(id));
+      auto* result_type = e->result_type()->UnwrapPtrIfNeeded();
+
+      // If we're putting a vector into the constructed composite we need to
+      // extract each of the values and insert them individually
+      if (result_type->IsVector()) {
+        auto* vec = result_type->AsVector();
+        auto result_type_id = GenerateTypeIfNeeded(vec->type());
+        if (result_type_id == 0) {
+          return 0;
+        }
+
+        for (uint32_t i = 0; i < vec->size(); ++i) {
+          auto extract = result_op();
+          auto extract_id = extract.to_i();
+
+          push_function_inst(spv::Op::OpCompositeExtract,
+                             {Operand::Int(result_type_id), extract,
+                              Operand::Int(id), Operand::Int(i)});
+
+          out << "_" << extract_id;
+          ops.push_back(Operand::Int(extract_id));
+        }
+      } else {
+        out << "_" << id;
+        ops.push_back(Operand::Int(id));
+      }
     }
 
     auto str = out.str();
diff --git a/src/writer/spirv/builder_constructor_expression_test.cc b/src/writer/spirv/builder_constructor_expression_test.cc
index efa3875..b7af4c8 100644
--- a/src/writer/spirv/builder_constructor_expression_test.cc
+++ b/src/writer/spirv/builder_constructor_expression_test.cc
@@ -65,7 +65,11 @@
 
   ast::TypeConstructorExpression t(&vec, std::move(vals));
 
+  Context ctx;
   ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(&t)) << td.error();
+
   Builder b(&mod);
   EXPECT_EQ(b.GenerateConstructorExpression(&t, true), 5u);
   ASSERT_FALSE(b.has_error()) << b.error();
@@ -120,6 +124,54 @@
 )");
 }
 
+TEST_F(BuilderTest, Constructor_Type_NonConstVector) {
+  ast::type::F32Type f32;
+  ast::type::VectorType vec2(&f32, 2);
+  ast::type::VectorType vec4(&f32, 4);
+
+  auto var = std::make_unique<ast::Variable>(
+      "ident", ast::StorageClass::kFunction, &vec2);
+
+  ast::ExpressionList vals;
+  vals.push_back(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::FloatLiteral>(&f32, 1.0f)));
+  vals.push_back(std::make_unique<ast::ScalarConstructorExpression>(
+      std::make_unique<ast::FloatLiteral>(&f32, 1.0f)));
+  vals.push_back(std::make_unique<ast::IdentifierExpression>("ident"));
+
+  ast::TypeConstructorExpression t(&vec4, std::move(vals));
+
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  td.RegisterVariableForTesting(var.get());
+  EXPECT_TRUE(td.DetermineResultType(&t)) << td.error();
+
+  Builder b(&mod);
+  b.push_function(Function{});
+  ASSERT_TRUE(b.GenerateFunctionVariable(var.get())) << b.error();
+
+  EXPECT_EQ(b.GenerateConstructorExpression(&t, false), 10u);
+  ASSERT_FALSE(b.has_error()) << b.error();
+
+  EXPECT_EQ(DumpInstructions(b.types()), R"(%4 = OpTypeFloat 32
+%3 = OpTypeVector %4 2
+%2 = OpTypePointer Function %3
+%5 = OpTypeVector %4 4
+%6 = OpConstant %4 1
+)");
+  EXPECT_EQ(DumpInstructions(b.functions()[0].variables()),
+            R"(%1 = OpVariable %2 Function
+)");
+
+  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()),
+            R"(%7 = OpLoad %3 %1
+%8 = OpCompositeExtract %4 %7 0
+%9 = OpCompositeExtract %4 %7 1
+%10 = OpCompositeConstruct %5 %6 %6 %8 %9
+)");
+}
+
 TEST_F(BuilderTest, Constructor_Type_Dedups) {
   ast::type::F32Type f32;
   ast::type::VectorType vec(&f32, 3);
@@ -134,7 +186,11 @@
 
   ast::TypeConstructorExpression t(&vec, std::move(vals));
 
+  Context ctx;
   ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(&t)) << td.error();
+
   Builder b(&mod);
   EXPECT_EQ(b.GenerateConstructorExpression(&t, true), 5u);
   EXPECT_EQ(b.GenerateConstructorExpression(&t, true), 5u);
diff --git a/src/writer/spirv/builder_function_variable_test.cc b/src/writer/spirv/builder_function_variable_test.cc
index 38e98bd..33ce0f1 100644
--- a/src/writer/spirv/builder_function_variable_test.cc
+++ b/src/writer/spirv/builder_function_variable_test.cc
@@ -30,6 +30,8 @@
 #include "src/ast/type_constructor_expression.h"
 #include "src/ast/variable.h"
 #include "src/ast/variable_decoration.h"
+#include "src/context.h"
+#include "src/type_determiner.h"
 #include "src/writer/spirv/builder.h"
 #include "src/writer/spirv/spv_dump.h"
 
@@ -74,10 +76,16 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
   ast::Variable v("var", ast::StorageClass::kOutput, &f32);
   v.set_constructor(std::move(init));
 
-  ast::Module mod;
+  td.RegisterVariableForTesting(&v);
+
   Builder b(&mod);
   b.push_function(Function{});
   EXPECT_TRUE(b.GenerateFunctionVariable(&v)) << b.error();
@@ -161,11 +169,17 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
   ast::Variable v("var", ast::StorageClass::kOutput, &f32);
   v.set_constructor(std::move(init));
   v.set_is_const(true);
 
-  ast::Module mod;
+  td.RegisterVariableForTesting(&v);
+
   Builder b(&mod);
   EXPECT_TRUE(b.GenerateFunctionVariable(&v)) << b.error();
   ASSERT_FALSE(b.has_error()) << b.error();
diff --git a/src/writer/spirv/builder_global_variable_test.cc b/src/writer/spirv/builder_global_variable_test.cc
index aad5670..8763d87 100644
--- a/src/writer/spirv/builder_global_variable_test.cc
+++ b/src/writer/spirv/builder_global_variable_test.cc
@@ -29,6 +29,8 @@
 #include "src/ast/type_constructor_expression.h"
 #include "src/ast/variable.h"
 #include "src/ast/variable_decoration.h"
+#include "src/context.h"
+#include "src/type_determiner.h"
 #include "src/writer/spirv/builder.h"
 #include "src/writer/spirv/spv_dump.h"
 
@@ -84,10 +86,15 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
   ast::Variable v("var", ast::StorageClass::kOutput, &f32);
   v.set_constructor(std::move(init));
+  td.RegisterVariableForTesting(&v);
 
-  ast::Module mod;
   Builder b(&mod);
   EXPECT_TRUE(b.GenerateGlobalVariable(&v)) << b.error();
   ASSERT_FALSE(b.has_error()) << b.error();
@@ -119,11 +126,16 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
   ast::Variable v("var", ast::StorageClass::kOutput, &f32);
   v.set_constructor(std::move(init));
   v.set_is_const(true);
+  td.RegisterVariableForTesting(&v);
 
-  ast::Module mod;
   Builder b(&mod);
   EXPECT_TRUE(b.GenerateGlobalVariable(&v)) << b.error();
   ASSERT_FALSE(b.has_error()) << b.error();
diff --git a/src/writer/spirv/builder_ident_expression_test.cc b/src/writer/spirv/builder_ident_expression_test.cc
index e69bb73..5fb39b5 100644
--- a/src/writer/spirv/builder_ident_expression_test.cc
+++ b/src/writer/spirv/builder_ident_expression_test.cc
@@ -52,13 +52,15 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
+  Context ctx;
+  ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
   ast::Variable v("var", ast::StorageClass::kOutput, &f32);
   v.set_constructor(std::move(init));
   v.set_is_const(true);
 
-  Context ctx;
-  ast::Module mod;
-  TypeDeterminer td(&ctx, &mod);
   td.RegisterVariableForTesting(&v);
 
   Builder b(&mod);
@@ -117,13 +119,14 @@
   auto init =
       std::make_unique<ast::TypeConstructorExpression>(&vec, std::move(vals));
 
-  ast::Variable v("var", ast::StorageClass::kOutput, &f32);
-  v.set_constructor(std::move(init));
-  v.set_is_const(true);
-
   Context ctx;
   ast::Module mod;
   TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(init.get())) << td.error();
+
+  ast::Variable v("var", ast::StorageClass::kOutput, &f32);
+  v.set_constructor(std::move(init));
+  v.set_is_const(true);
   td.RegisterVariableForTesting(&v);
 
   Builder b(&mod);
diff --git a/src/writer/spirv/builder_return_test.cc b/src/writer/spirv/builder_return_test.cc
index e6ab54c..48933a4 100644
--- a/src/writer/spirv/builder_return_test.cc
+++ b/src/writer/spirv/builder_return_test.cc
@@ -21,6 +21,8 @@
 #include "src/ast/type/f32_type.h"
 #include "src/ast/type/vector_type.h"
 #include "src/ast/type_constructor_expression.h"
+#include "src/context.h"
+#include "src/type_determiner.h"
 #include "src/writer/spirv/builder.h"
 #include "src/writer/spirv/spv_dump.h"
 
@@ -61,7 +63,11 @@
 
   ast::ReturnStatement ret(std::move(val));
 
+  Context ctx;
   ast::Module mod;
+  TypeDeterminer td(&ctx, &mod);
+  EXPECT_TRUE(td.DetermineResultType(&ret)) << td.error();
+
   Builder b(&mod);
   b.push_function(Function{});
   EXPECT_TRUE(b.GenerateReturnStatement(&ret));