Infer type of positional param from hint

1 files changed, 23 insertions, 3 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
index a7ea41d7..e7c0db4c 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionExpressionTests.java
@@ -10,9 +10,9 @@ import org.shedlang.compiler.util.P;
 
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.*;
-import static org.shedlang.compiler.typechecker.TypeCheckerTesting.typeCheckExpression;
 import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.isOptionalEmpty;
 import static org.zwobble.precisely.Matchers.isSequence;
@@ -26,7 +26,7 @@ public class TypeCheckerFunctionExpressionTests {
         var context = TypeCheckerContext.EMPTY
             .enterGlobal(P.map(Map.entry("Unit", Types.metaType(Types.UNIT))));
 
-        var typed = typeCheckExpression(untyped, context);
+        var typed = TypeCheckerTesting.typeCheckExpression(untyped, context);
 
         assertThat(
             typed.value(),
@@ -47,7 +47,7 @@ public class TypeCheckerFunctionExpressionTests {
             .build();
         var context = TypeCheckerContext.EMPTY;
 
-        var typed = typeCheckExpression(untyped, context);
+        var typed = TypeCheckerTesting.typeCheckExpression(untyped, context);
 
         assertThat(
             typed.value(),
@@ -55,4 +55,24 @@ public class TypeCheckerFunctionExpressionTests {
                 .withType(new FunctionType(List.of(), List.of(), Effects.NONE, Types.STRING))
         );
     }
+
+    @Test
+    public void positionalParamTypeCanBeInferredFromHint() {
+        var untyped = UntypedFunctionExpressionNode.builder()
+            .addPositionalParam("x", Optional.empty())
+            .build();
+        var context = TypeCheckerContext.EMPTY;
+
+        var typed = TypeChecker.typeCheckExpression(
+            untyped,
+            Optional.of(new FunctionType(List.of(Types.STRING), List.of(), Effects.NONE, Types.UNIT)),
+            context
+        );
+
+        assertThat(
+            typed.value(),
+            isTypedFunctionExpressionNode()
+                .withType(new FunctionType(List.of(Types.STRING), List.of(), Effects.NONE, Types.UNIT))
+        );
+    }
 }