From 854545383ef1145223c181127a40a9a2cc2be638 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Mon, 25 Dec 2023 12:05:46 +0000
Subject: Support field accesses on constructed types

---
 .../typechecker/TypeCheckerFieldAccessTests.java   | 73 ++++++++++++++++++++++
 1 file changed, 73 insertions(+)

(limited to 'src/test/java')

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFieldAccessTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFieldAccessTests.java
index 427db10f..e555181b 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFieldAccessTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFieldAccessTests.java
@@ -7,6 +7,7 @@ import org.shedlang.compiler.typechecker.errors.NoSuchFieldError;
 import org.shedlang.compiler.types.*;
 import org.shedlang.compiler.util.P;
 
+import java.util.List;
 import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -43,6 +44,78 @@ public class TypeCheckerFieldAccessTests {
         );
     }
 
+    @Test
+    public void canAccessFieldWithFixedTypeOnConstructedStructType() {
+        var untyped = Untyped.fieldAccess(
+            Untyped.reference("x"),
+            "size"
+        );
+        var genericType = Types.struct(NamespaceName.of("Example"), "List");
+        var typeConstructor = Types.typeConstructor(
+            List.of(TypeParam.forStructType(genericType, "T")),
+            genericType
+        );
+        var constructedType = Types.constructedType(
+            typeConstructor,
+            List.of(Types.STRING)
+        );
+        var structTypeInfo = StructTypeInfo.builder()
+            .addField("size", Types.INT)
+            .build();
+        var context = TypeCheckerContext.EMPTY
+            .enterGlobal(P.map(Map.entry("x", constructedType)))
+            .addStructTypeInfo(genericType, structTypeInfo);
+
+        var typed = typeCheckExpression(untyped, context);
+
+        assertThat(
+            typed.value(),
+            isTypedFieldAccessNode(
+                isTypedReferenceNode("x", constructedType),
+                "size",
+                Types.INT
+            )
+        );
+    }
+
+    @Test
+    public void canAccessFieldWithGenericTypeOnConstructedStructType() {
+        var untyped = Untyped.fieldAccess(
+            Untyped.reference("x"),
+            "value"
+        );
+        var genericType = Types.struct(NamespaceName.of("Example"), "Box");
+        var typeConstructor = Types.typeConstructor(
+            List.of(
+                TypeParam.forStructType(genericType, "T1"),
+                TypeParam.forStructType(genericType, "T2"),
+                TypeParam.forStructType(genericType, "T3")
+            ),
+            genericType
+        );
+        var constructedType = Types.constructedType(
+            typeConstructor,
+            List.of(Types.INT, Types.STRING, Types.BOOL)
+        );
+        var structTypeInfo = StructTypeInfo.builder()
+            .addField("value", TypeParam.forStructType(genericType, "T2"))
+            .build();
+        var context = TypeCheckerContext.EMPTY
+            .enterGlobal(P.map(Map.entry("x", constructedType)))
+            .addStructTypeInfo(genericType, structTypeInfo);
+
+        var typed = typeCheckExpression(untyped, context);
+
+        assertThat(
+            typed.value(),
+            isTypedFieldAccessNode(
+                isTypedReferenceNode("x", constructedType),
+                "value",
+                Types.STRING
+            )
+        );
+    }
+
     @Test
     public void canAccessFieldOnNamespaceType() {
         var untyped = Untyped.fieldAccess(
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