Implement type substitution for constructed types

1 files changed, 28 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java b/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java
index cd676d71..e9b04a95 100644
--- a/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java
+++ b/src/test/java/org/shedlang/compiler/types/TypeSubstitutionTests.java
@@ -36,6 +36,34 @@ public class TypeSubstitutionTests {
     }
 
     @Test
+    public void substitutingConstructedTypeSubstitutesArgs() {
+        var typeSubstitutionMap = TypeSubstitutionMap.of(
+            Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)
+        );
+
+        var result = TypeSubstitution.substitute(
+            Types.constructedType(
+                Types.typeConstructor(
+                    List.of(TypeParam.forStructType(STRUCT_TYPE_2, "T")),
+                    STRUCT_TYPE_2
+                ),
+                List.of(TypeParam.forStructType(STRUCT_TYPE, "T"))
+            ),
+            typeSubstitutionMap
+        );
+
+        assertThat(result, equalTo(
+            Types.constructedType(
+                Types.typeConstructor(
+                    List.of(TypeParam.forStructType(STRUCT_TYPE_2, "T")),
+                    STRUCT_TYPE_2
+                ),
+                List.of(Types.INT)
+            )
+        ));
+    }
+
+    @Test
     public void substitutingFunctionSubstitutesPositionalArgs() {
         var typeSubstitutionMap = TypeSubstitutionMap.of(
             Map.entry(TypeParam.forStructType(STRUCT_TYPE, "T"), Types.INT)