Check call to function with effect is marked with effects

11 files changed, 75 insertions, 12 deletions

diff --git a/src/main/java/org/shedlang/compiler/ShedCompiler.java b/src/main/java/org/shedlang/compiler/ShedCompiler.java
index bf26436e..d727aea5 100644
--- a/src/main/java/org/shedlang/compiler/ShedCompiler.java
+++ b/src/main/java/org/shedlang/compiler/ShedCompiler.java
@@ -42,6 +42,7 @@ public class ShedCompiler {
                 Map.entry("print", new FunctionType(
                     List.of(Types.STRING),
                     List.of(),
+                    Effects.IO,
                     Types.UNIT
                 ))
             ))
@@ -52,6 +53,7 @@ public class ShedCompiler {
                 Map.entry("print", new FunctionType(
                     List.of(Types.STRING),
                     List.of(),
+                    Effects.IO,
                     Types.UNIT
                 ))
             ));
diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java
index 417b9ad6..42783224 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java
@@ -42,6 +42,7 @@ public record TypedFunctionDefinitionNode(
                 params.named().stream()
                     .map(param -> new NamedParam(param.name(), param.type().value()))
                     .toList(),
+                effect.map(e -> e.value()).orElse(Effects.NONE),
                 returnType.value()
             ),
             source
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 770b7063..4d2b7326 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -142,6 +142,10 @@ public class TypeChecker {
         var typedArgs = argsResult.value();
         context = argsResult.context();
 
+        if (!receiverType.effect().equals(Effects.NONE) && !untyped.hasEffects()) {
+            throw new CallIsMissingEffectsError(receiverType.effect(), untyped.source());
+        }
+
         return context.toResult(new TypedCallNode(
             typedReceiver,
             typedArgs,
diff --git a/src/main/java/org/shedlang/compiler/typechecker/errors/CallIsMissingEffectsError.java b/src/main/java/org/shedlang/compiler/typechecker/errors/CallIsMissingEffectsError.java
new file mode 100644
index 00000000..083d9a03
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/typechecker/errors/CallIsMissingEffectsError.java
@@ -0,0 +1,18 @@
+package org.shedlang.compiler.typechecker.errors;
+
+import org.shedlang.compiler.errors.SourceError;
+import org.shedlang.compiler.sources.Source;
+import org.shedlang.compiler.types.Effect;
+
+public class CallIsMissingEffectsError extends SourceError {
+    private final Effect effect;
+
+    public CallIsMissingEffectsError(Effect effect, Source source) {
+        super("Function has effect, but call is missing effect: " + effect.describe(), source);
+        this.effect = effect;
+    }
+
+    public Effect effect() {
+        return effect;
+    }
+}
diff --git a/src/main/java/org/shedlang/compiler/types/Effect.java b/src/main/java/org/shedlang/compiler/types/Effect.java
index 257a3847..7e8bc203 100644
--- a/src/main/java/org/shedlang/compiler/types/Effect.java
+++ b/src/main/java/org/shedlang/compiler/types/Effect.java
@@ -1,4 +1,4 @@
 package org.shedlang.compiler.types;
 
-public sealed interface Effect extends TypeLevelValue permits IoEffect {
+public sealed interface Effect extends TypeLevelValue permits IoEffect, NoneEffect {
 }
diff --git a/src/main/java/org/shedlang/compiler/types/Effects.java b/src/main/java/org/shedlang/compiler/types/Effects.java
index 820d31c5..c894a58b 100644
--- a/src/main/java/org/shedlang/compiler/types/Effects.java
+++ b/src/main/java/org/shedlang/compiler/types/Effects.java
@@ -4,5 +4,7 @@ public class Effects {
     private Effects() {
     }
 
+    public static final Effect NONE = NoneEffect.INSTANCE;
+
     public static final Effect IO = IoEffect.INSTANCE;
 }
diff --git a/src/main/java/org/shedlang/compiler/types/FunctionType.java b/src/main/java/org/shedlang/compiler/types/FunctionType.java
index 22d3487b..e40439f7 100644
--- a/src/main/java/org/shedlang/compiler/types/FunctionType.java
+++ b/src/main/java/org/shedlang/compiler/types/FunctionType.java
@@ -8,10 +8,11 @@ import java.util.List;
 public record FunctionType(
     List<Type> positionalParams,
     List<NamedParam> namedParams,
+    Effect effect,
     Type returnType
 ) implements Type {
     public static Builder builder() {
-        return new Builder(Empty.vector(), Empty.vector(), Types.UNIT);
+        return new Builder(Empty.vector(), Empty.vector(), Effects.NONE, Types.UNIT);
     }
 
     @Override
@@ -23,23 +24,28 @@ public record FunctionType(
     public record Builder(
         PVector<Type> positionalParams,
         PVector<NamedParam> namedParams,
+        Effect effect,
         Type returnType
     ) {
         public FunctionType build() {
-            return new FunctionType(positionalParams, namedParams, returnType);
+            return new FunctionType(positionalParams, namedParams, effect, returnType);
         }
 
         public Builder addNamedParam(String name, Type type) {
             var namedParam = new NamedParam(name, type);
-            return new Builder(positionalParams, namedParams.plus(namedParam), returnType);
+            return new Builder(positionalParams, namedParams.plus(namedParam), effect, returnType);
         }
 
         public Builder addPositionalParam(Type type) {
-            return new Builder(positionalParams.plus(type), namedParams, returnType);
+            return new Builder(positionalParams.plus(type), namedParams, effect, returnType);
+        }
+
+        public Builder withEffect(Effect effect) {
+            return new Builder(positionalParams, namedParams, effect, returnType);
         }
 
         public Builder withReturnType(Type returnType) {
-            return new Builder(positionalParams, namedParams, returnType);
+            return new Builder(positionalParams, namedParams, effect, returnType);
         }
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/types/NoneEffect.java b/src/main/java/org/shedlang/compiler/types/NoneEffect.java
new file mode 100644
index 00000000..e6fe5f95
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/types/NoneEffect.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.types;
+
+public record NoneEffect() implements Effect {
+    static final NoneEffect INSTANCE = new NoneEffect();
+
+    @Override
+    public String describe() {
+        return "None";
+    }
+}
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
index 24ded26f..ad1ab07e 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
@@ -4,6 +4,7 @@ import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.typechecker.errors.*;
 import org.shedlang.compiler.typechecker.typesets.TypeSets;
+import org.shedlang.compiler.types.Effects;
 import org.shedlang.compiler.types.FunctionType;
 import org.shedlang.compiler.types.Types;
 import org.shedlang.compiler.util.P;
@@ -252,4 +253,25 @@ public class TypeCheckerCallTests {
 
         assertThat(error.argName(), equalTo("x"));
     }
+
+    @Test
+    public void givenFunctionHasEffectsWhenCallingFunctionWithoutExplicitEffectsThenErrorIsThrown() {
+        var untyped = Untyped.call(
+            Untyped.reference("f"),
+            List.of()
+        );
+        var functionType = FunctionType.builder()
+            .withEffect(Effects.IO)
+            .withReturnType(Types.UNIT)
+            .build();
+        var context = TypeCheckerContext.EMPTY
+            .enter(P.map(Map.entry("f", functionType)));
+
+        var error = assertThrows(
+            CallIsMissingEffectsError.class,
+            () -> TypeChecker.typeCheckExpression(untyped, context)
+        );
+
+        assertThat(error.effect(), equalTo(Effects.IO));
+    }
 }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
index 26ea2693..b7b2d66e 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
@@ -36,7 +36,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 .withEffect(isOptionalEmpty())
                 .withReturnType(isTypedTypeLevelReferenceNode("Unit", Types.UNIT))
                 .withBody(isSequence())
-                .withType(new FunctionType(List.of(), List.of(), Types.UNIT))
+                .withType(new FunctionType(List.of(), List.of(), Effects.NONE, Types.UNIT))
         );
     }
 
@@ -68,6 +68,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 .withType(new FunctionType(
                     List.of(Types.STRING),
                     List.of(new NamedParam("y", Types.INT)),
+                    Effects.NONE,
                     Types.UNIT
                 ))
         );
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerNamespaceTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerNamespaceTests.java
index b9b6679c..8d537515 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerNamespaceTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerNamespaceTests.java
@@ -3,10 +3,7 @@ package org.shedlang.compiler.typechecker;
 import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.ast.untyped.UntypedFunctionDefinitionNode;
-import org.shedlang.compiler.types.FunctionType;
-import org.shedlang.compiler.types.NamespaceName;
-import org.shedlang.compiler.types.NamespaceTypeInfo;
-import org.shedlang.compiler.types.Types;
+import org.shedlang.compiler.types.*;
 import org.shedlang.compiler.util.P;
 
 import java.util.List;
@@ -77,7 +74,7 @@ public class TypeCheckerNamespaceTests {
         assertThat(
             result.context().namespaceTypeInfo().get(namespaceName),
             equalTo(new NamespaceTypeInfo(P.orderedMap(
-                Map.entry("f", new FunctionType(List.of(), List.of(), Types.UNIT))
+                Map.entry("f", new FunctionType(List.of(), List.of(), Effects.NONE, Types.UNIT))
             )))
         );
     }