Use return type in function body

1 files changed, 23 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
index a03a1f44..25b9c158 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
@@ -4,6 +4,8 @@ import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.ast.untyped.UntypedCallNode;
 import org.shedlang.compiler.ast.untyped.UntypedFunctionDefinitionNode;
+import org.shedlang.compiler.typechecker.errors.UnexpectedTypeError;
+import org.shedlang.compiler.typechecker.typesets.TypeSets;
 import org.shedlang.compiler.types.Effects;
 import org.shedlang.compiler.types.FunctionType;
 import org.shedlang.compiler.types.NamedParam;
@@ -13,6 +15,7 @@ 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.*;
@@ -199,6 +202,26 @@ public class TypeCheckerFunctionDefinitionTests {
     }
 
     @Test
+    public void bodyHasReturnTypeAsDefinedInSignature() {
+        var untyped = UntypedFunctionDefinitionNode.builder()
+            .withReturnType(Untyped.typeLevelReference("String"))
+            .addStatement(Untyped.return_(Untyped.intLiteral(42)))
+            .build();
+        var context = TypeCheckerContext.EMPTY
+            .enterNamespaceWithDefinedVariables(P.map(
+                Map.entry("String", Types.metaType(Types.STRING))
+            ));
+
+        var error = assertThrows(
+            UnexpectedTypeError.class,
+            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+        );
+
+        assertThat(error.expected(), equalTo(TypeSets.type(Types.STRING)));
+        assertThat(error.actual(), equalTo(Types.INT));
+    }
+
+    @Test
     public void freeVariablesIncludeVariablesReferencedInFunctionButDefinedOutsideOfFunction() {
         var untyped = UntypedFunctionDefinitionNode.builder()
             .withReturnType(Untyped.typeLevelReference("Unit"))