2 files changed, 21 insertions, 3 deletions
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 228f1fa0..1dd4b118 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -403,7 +403,7 @@ public class TypeChecker {
         var expression = expressionResult.value();
         context = expressionResult.context();
         
-        var targetResult = typeCheckTarget(val.target(), context);
+        var targetResult = typeCheckTarget(val.target(), expression.type(), context);
         var target = targetResult.value();
         context = targetResult.context();
         
@@ -412,11 +412,15 @@ public class TypeChecker {
 
     private static TypeCheckerResult<TypedTargetNode> typeCheckTarget(
         UntypedTargetNode target,
+        Type expressionType,
         TypeCheckerContext context
     ) {
         return switch (target) {
-            case UntypedTargetNode.Variable variable ->
-                context.toResult(new TypedTargetNode.Variable(variable.name(), target.source()));
+            case UntypedTargetNode.Variable variable -> {
+                context = context.define(variable.name(), expressionType);
+
+                yield context.toResult(new TypedTargetNode.Variable(variable.name(), target.source()));
+            }
         };
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
index 71a02101..2cf99f9f 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
@@ -71,6 +71,20 @@ public class TypeCheckerContext {
         return Optional.ofNullable(environment.get(name));
     }
 
+    public TypeCheckerContext define(
+        String name,
+        Type type
+    ) {
+        // TODO: check if already defined
+        return new TypeCheckerContext(
+            this.environment.plus(name, type),
+            this.effect,
+            this.boundVariables,
+            this.freeVariables,
+            this.namespaceTypeInfo
+        );
+    }
+
     public Effect effect() {
         return effect;
     }