Require variables to be declared before definition

3 files changed, 74 insertions, 22 deletions

diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
index 650f23d5..f8529083 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
@@ -2,11 +2,13 @@ package org.shedlang.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.sources.Sources;
+import org.shedlang.compiler.typechecker.errors.UnknownVariableError;
 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.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.equalTo;
 import static org.zwobble.precisely.Matchers.isOptionalOf;
@@ -25,4 +27,19 @@ public class TypeCheckerContextTests {
 
         assertThat(result.value(), isOptionalOf(equalTo(TypeCheckerContext.defined(Types.STRING))));
     }
+
+    @Test
+    public void givenVariableIsUnknownWhenVariableIsDefinedThenErrorIsThrown() {
+        var context = TypeCheckerContext.EMPTY
+            .enterNamespace(P.map(
+                Map.entry("y", TypeCheckerContext.undefined())
+            ));
+
+        var error = assertThrows(
+            UnknownVariableError.class,
+            () -> context.define("x", Types.STRING, Sources.NULL)
+        );
+
+        assertThat(error.variableName(), equalTo("x"));
+    }
 }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
index a39ec685..ee88b457 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerFunctionDefinitionTests.java
@@ -1,6 +1,7 @@
 package org.shedlang.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.ast.typed.TypedNamespaceStatementNode;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.ast.untyped.UntypedCallNode;
 import org.shedlang.compiler.ast.untyped.UntypedFunctionDefinitionNode;
@@ -30,7 +31,7 @@ public class TypeCheckerFunctionDefinitionTests {
         var context = TypeCheckerContext.EMPTY
             .enterNamespaceWithDefinedVariables(P.map(Map.entry("Unit", Types.metaType(Types.UNIT))));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -58,7 +59,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -90,7 +91,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -108,7 +109,7 @@ public class TypeCheckerFunctionDefinitionTests {
         var context = TypeCheckerContext.EMPTY
             .enterNamespaceWithDefinedVariables(P.map(Map.entry("Unit", Types.metaType(Types.UNIT))));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -132,7 +133,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -156,7 +157,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -170,6 +171,7 @@ public class TypeCheckerFunctionDefinitionTests {
     @Test
     public void bodyHasEffectAsDefinedInSignature() {
         var untyped = UntypedFunctionDefinitionNode.builder()
+            .withName("g")
             .withEffect(Untyped.typeLevelReference("Io"))
             .withReturnType(Untyped.typeLevelReference("Unit"))
             .addStatement(Untyped.expressionStatement(
@@ -190,7 +192,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -214,7 +216,7 @@ public class TypeCheckerFunctionDefinitionTests {
 
         var error = assertThrows(
             UnexpectedTypeError.class,
-            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+            () -> typeCheckNamespaceStatement(untyped, context)
         );
 
         assertThat(error.expected(), equalTo(TypeSets.type(Types.STRING)));
@@ -231,7 +233,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        typeCheckNamespaceStatement(untyped, context);
     }
 
     @Test
@@ -246,7 +248,7 @@ public class TypeCheckerFunctionDefinitionTests {
 
         var error = assertThrows(
             UnexpectedTypeError.class,
-            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+            () -> typeCheckNamespaceStatement(untyped, context)
         );
 
         assertThat(error.expected(), equalTo(TypeSets.type(Types.STRING)));
@@ -264,7 +266,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("String", Types.metaType(Types.STRING))
             ));
 
-        TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        typeCheckNamespaceStatement(untyped, context);
     }
 
     @Test
@@ -280,7 +282,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("y", Types.STRING)
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -304,7 +306,7 @@ public class TypeCheckerFunctionDefinitionTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -312,4 +314,15 @@ public class TypeCheckerFunctionDefinitionTests {
                 .withFreeVariables(containsExactly())
         );
     }
+
+    private static TypeCheckerResult<? extends TypedNamespaceStatementNode> typeCheckNamespaceStatement(
+        UntypedFunctionDefinitionNode untyped,
+        TypeCheckerContext context
+    ) {
+        var environment = TypeChecker.declareVariables(untyped, EnvironmentBuilder.EMPTY);
+
+        context = context.enterNamespace(environment.build());
+
+        return TypeChecker.typeCheckNamespaceStatement(untyped, context);
+    }
 }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerValTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerValTests.java
index 11a66f12..44abec8b 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerValTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerValTests.java
@@ -1,9 +1,9 @@
 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.ast.untyped.UntypedNamespaceNode;
+import org.shedlang.compiler.ast.typed.TypedFunctionStatementNode;
+import org.shedlang.compiler.ast.typed.TypedNamespaceStatementNode;
+import org.shedlang.compiler.ast.untyped.*;
 import org.shedlang.compiler.typechecker.errors.DuplicateVariableName;
 import org.shedlang.compiler.typechecker.errors.ReferenceBeforeDefinitionError;
 import org.shedlang.compiler.types.Types;
@@ -21,7 +21,7 @@ public class TypeCheckerValTests {
     public void canTypeCheckAsFunctionStatement() {
         var untyped = Untyped.val(Untyped.targetVariable("x"), Untyped.stringLiteral("hello"));
 
-        var typed = TypeChecker.typeCheckFunctionStatement(untyped, TypeCheckerContext.EMPTY);
+        var typed = typeCheckFunctionStatement(untyped, TypeCheckerContext.EMPTY);
 
         assertThat(typed.value(), isTypedValNode(
             isTypedTargetVariable("x"),
@@ -33,7 +33,7 @@ public class TypeCheckerValTests {
     public void canTypeCheckAsNamespaceStatement() {
         var untyped = Untyped.val(Untyped.targetVariable("x"), Untyped.stringLiteral("hello"));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, TypeCheckerContext.EMPTY);
+        var typed = typeCheckNamespaceStatement(untyped, TypeCheckerContext.EMPTY);
 
         assertThat(typed.value(), isTypedValNode(
             isTypedTargetVariable("x"),
@@ -52,7 +52,7 @@ public class TypeCheckerValTests {
                 Map.entry("Unit", Types.metaType(Types.UNIT))
             ));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(
             typed.value(),
@@ -100,7 +100,7 @@ public class TypeCheckerValTests {
 
         var error = assertThrows(
             ReferenceBeforeDefinitionError.class,
-            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+            () -> typeCheckNamespaceStatement(untyped, context)
         );
 
         assertThat(error.variableName(), equalTo("x"));
@@ -120,7 +120,7 @@ public class TypeCheckerValTests {
 
         var error = assertThrows(
             ReferenceBeforeDefinitionError.class,
-            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+            () -> typeCheckNamespaceStatement(untyped, context)
         );
 
         assertThat(error.variableName(), equalTo("x"));
@@ -139,9 +139,31 @@ public class TypeCheckerValTests {
 
         var error = assertThrows(
             DuplicateVariableName.class,
-            () -> TypeChecker.typeCheckNamespaceStatement(untyped, context)
+            () -> typeCheckNamespaceStatement(untyped, context)
         );
 
         assertThat(error.variableName(), equalTo("x"));
     }
+
+    private static TypeCheckerResult<? extends TypedFunctionStatementNode> typeCheckFunctionStatement(
+        UntypedFunctionStatementNode untyped,
+        TypeCheckerContext context
+    ) {
+        var environment = TypeChecker.declareVariables(untyped, EnvironmentBuilder.EMPTY);
+
+        context = context.enterNamespace(environment.build());
+
+        return TypeChecker.typeCheckFunctionStatement(untyped, context);
+    }
+
+    private static TypeCheckerResult<? extends TypedNamespaceStatementNode> typeCheckNamespaceStatement(
+        UntypedNamespaceStatementNode untyped,
+        TypeCheckerContext context
+    ) {
+        var environment = TypeChecker.declareVariables(untyped, EnvironmentBuilder.EMPTY);
+
+        context = context.enterNamespace(environment.build());
+
+        return TypeChecker.typeCheckNamespaceStatement(untyped, context);
+    }
 }