Disallow returns in effect handlers

1 files changed, 13 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionReturnTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionReturnTests.java
index da130bcc..650d1531 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionReturnTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionReturnTests.java
@@ -2,6 +2,7 @@ package org.shedlang.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
+import org.shedlang.compiler.typechecker.errors.CannotReturnFromEffectHandlerFieldError;
 import org.shedlang.compiler.typechecker.errors.CannotReturnOutsideOfFunctionError;
 import org.shedlang.compiler.typechecker.errors.UnexpectedTypeError;
 import org.shedlang.compiler.typechecker.typesets.TypeSets;
@@ -53,6 +54,18 @@ public class TypeCheckerFunctionReturnTests {
     }
 
     @Test
+    public void whenInEffectHandlerThenReturnIsForbidden() {
+        var untyped = Untyped.functionReturn(Untyped.stringLiteral("hello"));
+        var context = TypeCheckerContext.EMPTY
+            .enterFunction(P.map(), Effects.NONE, ReturnTypeState.effectHandler(Types.UNIT));
+
+        assertThrows(
+            CannotReturnFromEffectHandlerFieldError.class,
+            () -> TypeChecker.typeCheckFunctionStatement(untyped, context)
+        );
+    }
+
+    @Test
     public void canReturnSubtypeOfReturnType() {
         var untyped = Untyped.functionReturn(Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY