Check call to function without effects has no effects

2 files changed, 17 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 4d2b7326..591d4810 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -142,10 +142,16 @@ public class TypeChecker {
         var typedArgs = argsResult.value();
         context = argsResult.context();
 
-        if (!receiverType.effect().equals(Effects.NONE) && !untyped.hasEffects()) {
+        var receiverHasEffects = !receiverType.effect().equals(Effects.NONE);
+
+        if (receiverHasEffects && !untyped.hasEffects()) {
             throw new CallIsMissingEffectsError(receiverType.effect(), untyped.source());
         }
 
+        if (!receiverHasEffects && untyped.hasEffects()) {
+            throw new FunctionHasNoEffectsError(untyped.source());
+        }
+
         return context.toResult(new TypedCallNode(
             typedReceiver,
             typedArgs,
diff --git a/src/main/java/org/shedlang/compiler/typechecker/errors/FunctionHasNoEffectsError.java b/src/main/java/org/shedlang/compiler/typechecker/errors/FunctionHasNoEffectsError.java
new file mode 100644
index 00000000..162109a0
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/typechecker/errors/FunctionHasNoEffectsError.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.typechecker.errors;
+
+import org.shedlang.compiler.errors.SourceError;
+import org.shedlang.compiler.sources.Source;
+
+public class FunctionHasNoEffectsError extends SourceError {
+    public FunctionHasNoEffectsError(Source source) {
+        super("Call has effect, but function has no effects", source);
+    }
+}