Infer named param types from hint

1 files changed, 21 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
index e7c0db4c..d48ea972 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
@@ -5,6 +5,7 @@ import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.ast.untyped.UntypedFunctionExpressionNode;
 import org.shedlang.compiler.types.Effects;
 import org.shedlang.compiler.types.FunctionType;
+import org.shedlang.compiler.types.NamedParam;
 import org.shedlang.compiler.types.Types;
 import org.shedlang.compiler.util.P;
 
@@ -75,4 +76,24 @@ public class TypeCheckerFunctionExpressionTests {
                 .withType(new FunctionType(List.of(Types.STRING), List.of(), Effects.NONE, Types.UNIT))
         );
     }
+
+    @Test
+    public void namedParamTypeCanBeInferredFromHint() {
+        var untyped = UntypedFunctionExpressionNode.builder()
+            .addNamedParam("x", Optional.empty())
+            .build();
+        var context = TypeCheckerContext.EMPTY;
+
+        var typed = TypeChecker.typeCheckExpression(
+            untyped,
+            Optional.of(new FunctionType(List.of(), List.of(new NamedParam("x", Types.STRING)), Effects.NONE, Types.UNIT)),
+            context
+        );
+
+        assertThat(
+            typed.value(),
+            isTypedFunctionExpressionNode()
+                .withType(new FunctionType(List.of(), List.of(new NamedParam("x", Types.STRING)), Effects.NONE, Types.UNIT))
+        );
+    }
 }