Check operand types for binary operation

1 files changed, 31 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
index d752fe94..e7721d1d 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
@@ -2,8 +2,11 @@ package org.shedlang.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
+import org.shedlang.compiler.ast.untyped.UntypedBinaryOperator;
+import org.shedlang.compiler.typechecker.errors.UnsupportedBinaryOperationError;
 import org.shedlang.compiler.types.Types;
 
+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.equalTo;
@@ -61,4 +64,32 @@ public class TypeCheckerBinaryOperationTests {
         ));
         assertThat(typed.value().type(), equalTo(Types.INT));
     }
+
+    @Test
+    public void whenLeftOperandIsIntAndRightOperandIsNotIntThenExpressionFailsToTypeCheck() {
+        var untyped = Untyped.add(Untyped.stringLiteral("42"), Untyped.intLiteral(47));
+
+        var error = assertThrows(
+            UnsupportedBinaryOperationError.class,
+            () -> TypeChecker.typeCheckExpression(untyped, TypeCheckerContext.EMPTY)
+        );
+
+        assertThat(error.operator(), equalTo(UntypedBinaryOperator.ADD));
+        assertThat(error.left(), equalTo(Types.STRING));
+        assertThat(error.right(), equalTo(Types.INT));
+    }
+
+    @Test
+    public void whenLeftOperandIsNotIntAndRightOperandIsIntThenExpressionFailsToTypeCheck() {
+        var untyped = Untyped.add(Untyped.intLiteral(42), Untyped.stringLiteral("47"));
+
+        var error = assertThrows(
+            UnsupportedBinaryOperationError.class,
+            () -> TypeChecker.typeCheckExpression(untyped, TypeCheckerContext.EMPTY)
+        );
+
+        assertThat(error.operator(), equalTo(UntypedBinaryOperator.ADD));
+        assertThat(error.left(), equalTo(Types.INT));
+        assertThat(error.right(), equalTo(Types.STRING));
+    }
 }