From 23d625dbaf27186dcf74014b6a25011612523178 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 29 Dec 2023 11:46:49 +0000
Subject: Support constructed struct type as case in when expression

---
 .../compiler/typechecker/TypeCheckerWhenTests.java | 64 ++++++++++++++++++++++
 1 file changed, 64 insertions(+)

(limited to 'src/test/java')

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerWhenTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerWhenTests.java
index d0ea43cb..dcf0979d 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerWhenTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerWhenTests.java
@@ -200,6 +200,70 @@ public class TypeCheckerWhenTests {
         ));
     }
 
+    @Test
+    public void variantCanBeConstructedSumType() {
+        var variantTypeConstructor1 = Types.typeConstructor(
+            List.of(TypeParam.forStructType(VARIANT_TYPE_1, "T")),
+            VARIANT_TYPE_1
+        );
+        // TODO: check type checking fails when constructed type arg for case is incorrect
+        var constructedVariantType1 = Types.constructedType(
+            variantTypeConstructor1,
+            List.of(Types.STRING)
+        );
+        var untyped = Untyped.when(
+            Untyped.reference("x"),
+            List.of(
+                Untyped.whenCase(
+                    Untyped.constructedType(
+                        Untyped.typeLevelReference(VARIANT_TYPE_1.name()),
+                        List.of(Untyped.typeLevelReference("String"))
+                    ),
+                    Untyped.block(List.of(
+                        Untyped.blockReturn(Untyped.stringLiteral("a"))
+                    ))
+                ),
+                Untyped.whenCase(
+                    Untyped.typeLevelReference(VARIANT_TYPE_2.name()),
+                    Untyped.block(List.of(
+                        Untyped.blockReturn(Untyped.stringLiteral("b"))
+                    ))
+                )
+            )
+        );
+        var context = TypeCheckerContext.EMPTY
+            .addSumTypeInfo(SUM_TYPE, new SumTypeInfo(P.orderedSet(
+                SumVariant.constructedStruct(constructedVariantType1),
+                SumVariant.struct(VARIANT_TYPE_2)
+            )))
+            .enterGlobal(P.map(
+                Map.entry("String", Types.metaType(Types.STRING)),
+                Map.entry("x", SUM_TYPE),
+                Map.entry(VARIANT_TYPE_1.name(), Types.typeConstructorType(variantTypeConstructor1)),
+                Map.entry(VARIANT_TYPE_2.name(), Types.metaType(VARIANT_TYPE_2))
+            ));
+
+        var result = typeCheckExpression(untyped, context);
+
+        assertThat(result.value(), isTypedWhenNode(
+            isTypedReferenceNode("x", SUM_TYPE),
+            isSequence(
+                isTypedWhenCaseNode(
+                    equalTo(SumVariant.constructedStruct(constructedVariantType1)),
+                    isTypedBlockNode(isSequence(
+                        isTypedBlockReturnNode(isTypedStringLiteralNode("a"))
+                    ))
+                ),
+                isTypedWhenCaseNode(
+                    equalTo(SumVariant.struct(VARIANT_TYPE_2)),
+                    isTypedBlockNode(isSequence(
+                        isTypedBlockReturnNode(isTypedStringLiteralNode("b"))
+                    ))
+                )
+            )
+        ));
+    }
+
     @Test
     public void whenCaseBodiesHaveSameTypeThenExpressionTypeIsThatType() {
         var untyped = Untyped.when(
-- 
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