From f544626a85a2e5fedaec200c231b69728fbf99e9 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 17 Sep 2023 17:34:54 +0100
Subject: Type check assignment to tuple target

---
 .../compiler/ast/typed/TypedNodeMatchers.java      |  9 +++++
 .../org/shedlang/compiler/ast/untyped/Untyped.java |  4 +++
 .../typechecker/TypeCheckerAssignTests.java        | 41 +++++++++++++++++++---
 3 files changed, 50 insertions(+), 4 deletions(-)

(limited to 'src/test/java')

diff --git a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
index 37a583ba..9f66f16c 100644
--- a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
@@ -228,6 +228,15 @@ public class TypedNodeMatchers {
         );
     }
 
+    public static Matcher<TypedTargetNode> isTypedTargetTuple(
+        Matcher<Iterable<? extends TypedTargetNode>> elements
+    ) {
+        return instanceOf(
+            TypedTargetNode.Tuple.class,
+            has("elements", x -> x.elements(), elements)
+        );
+    }
+
     public static Matcher<TypedTargetNode> isTypedTargetVal(String name) {
         return instanceOf(
             TypedTargetNode.Val.class,
diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
index a41ab8d7..8c046e4a 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
@@ -154,6 +154,10 @@ public class Untyped {
         return new UntypedTargetNode.Reassign(name, Sources.NULL);
     }
 
+    public static UntypedTargetNode targetTuple(List<UntypedTargetNode> elements) {
+        return new UntypedTargetNode.Tuple(elements, Sources.NULL);
+    }
+
     public static UntypedTargetNode targetVal(String name) {
         return new UntypedTargetNode.Val(name, Sources.NULL);
     }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
index df18c0bb..20f3ef5d 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
@@ -12,16 +12,17 @@ import org.shedlang.compiler.typechecker.typesets.TypeSets;
 import org.shedlang.compiler.types.Types;
 import org.shedlang.compiler.util.P;
 
+import java.util.List;
 import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.*;
 import static org.zwobble.precisely.AssertThat.assertThat;
-import static org.zwobble.precisely.Matchers.equalTo;
+import static org.zwobble.precisely.Matchers.*;
 
 public class TypeCheckerAssignTests {
     @Test
-    public void canTypeCheckAssign() {
+    public void canTypeCheckReassign() {
         var untyped = Untyped.assign(Untyped.targetReassign("x"), Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
@@ -37,7 +38,7 @@ public class TypeCheckerAssignTests {
     }
 
     @Test
-    public void whenExpressionIsNotSubTypeOfTargetVariableThenErrorIsThrown() {
+    public void whenExpressionIsNotSubTypeOfReassignTargetVariableThenErrorIsThrown() {
         var untyped = Untyped.assign(Untyped.targetReassign("x"), Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
@@ -54,7 +55,7 @@ public class TypeCheckerAssignTests {
     }
 
     @Test
-    public void whenTargetIsNotVarThenErrorIsThrown() {
+    public void whenReassignTargetIsNotVarThenErrorIsThrown() {
         var untyped = Untyped.assign(Untyped.targetReassign("x"), Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
@@ -67,6 +68,38 @@ public class TypeCheckerAssignTests {
         );
     }
 
+    @Test
+    public void canTypeCheckTupleTarget() {
+        var untyped = Untyped.assign(
+            Untyped.targetTuple(List.of(
+                Untyped.targetVal("a"),
+                Untyped.targetVal("b"),
+                Untyped.targetVal("c")
+            )),
+            Untyped.reference("x")
+        );
+        var tupleType = Types.tuple(List.of(
+            Types.STRING,
+            Types.INT,
+            Types.BOOL
+        ));
+        var context = TypeCheckerContext.EMPTY
+            .enterNamespace(P.map(
+                Map.entry("x", Variable.defined(tupleType, VariableType.VAR))
+            ));
+
+        var typed = typeCheckFunctionStatement(untyped, context);
+
+        assertThat(typed.value(), isTypedAssignNode(
+            isTypedTargetTuple(isSequence(
+                isTypedTargetVal("a"),
+                isTypedTargetVal("b"),
+                isTypedTargetVal("c")
+            )),
+            anything()
+        ));
+    }
+
     private static TypeCheckerResult<? extends TypedFunctionStatementNode> typeCheckFunctionStatement(
         UntypedFunctionStatementNode untyped,
         TypeCheckerContext context
-- 
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