From 92bcb4b11954348daa759eb967d2b15c12744dc5 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 9 Jun 2023 18:15:27 +0100
Subject: Type check references

---
 .../compiler/ast/typed/TypedNodeMatchers.java      |  9 +++++
 .../org/shedlang/compiler/ast/untyped/Untyped.java |  4 +++
 .../typechecker/TypeCheckerReferenceTests.java     | 40 ++++++++++++++++++++++
 3 files changed, 53 insertions(+)
 create mode 100644 src/test/java/org/shedlang/compiler/typechecker/TypeCheckerReferenceTests.java

(limited to 'src/test/java')

diff --git a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
index 35b15902..9c2164b5 100644
--- a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
@@ -1,5 +1,6 @@
 package org.shedlang.compiler.ast.typed;
 
+import org.shedlang.compiler.types.Type;
 import org.zwobble.precisely.Matcher;
 
 import static org.zwobble.precisely.Matchers.*;
@@ -8,6 +9,14 @@ public class TypedNodeMatchers {
     private TypedNodeMatchers() {
     }
 
+    public static Matcher<TypedExpressionNode> isTypedReferenceNode(String name, Type type) {
+        return instanceOf(
+            TypedReferenceNode.class,
+            has("name", x -> x.name(), equalTo(name)),
+            has("type", x -> x.type(), equalTo(type))
+        );
+    }
+
     public static Matcher<TypedExpressionNode> isTypedStringLiteralNode(String value) {
         return instanceOf(
             TypedStringLiteralNode.class,
diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
index 932ceae1..32a01ec4 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
@@ -6,6 +6,10 @@ public class Untyped {
     private Untyped() {
     }
 
+    public static UntypedReferenceNode reference(String name) {
+        return new UntypedReferenceNode(name, Sources.NULL);
+    }
+
     public static UntypedStringLiteralNode stringLiteral(String value) {
         return new UntypedStringLiteralNode(value, Sources.NULL);
     }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerReferenceTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerReferenceTests.java
new file mode 100644
index 00000000..2e1d3066
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerReferenceTests.java
@@ -0,0 +1,40 @@
+package org.shedlang.compiler.typechecker;
+
+import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.ast.untyped.Untyped;
+import org.shedlang.compiler.types.Types;
+import org.shedlang.compiler.util.P;
+
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.isTypedReferenceNode;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class TypeCheckerReferenceTests {
+    @Test
+    public void whenNameIsBoundInEnvironmentThenTypeIsUsedFromEnvironment() {
+        var untyped = Untyped.reference("x");
+        var context = TypeCheckerContext.EMPTY
+            .enter(P.map(Map.entry("x", Types.STRING)));
+
+        var typed = TypeChecker.typeCheckExpression(untyped, context);
+
+        assertThat(typed, isTypedReferenceNode("x", Types.STRING));
+    }
+
+    @Test
+    public void whenNameIsNotBoundInEnvironmentThenErrorIsThrown() {
+        var untyped = Untyped.reference("x");
+        var context = TypeCheckerContext.EMPTY
+            .enter(P.map(Map.entry("y", Types.STRING)));
+
+        var error = assertThrows(
+            UnknownVariableError.class,
+            () -> TypeChecker.typeCheckExpression(untyped, context)
+        );
+
+        assertThat(error.variableName(), equalTo("x"));
+    }
+}
-- 
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