From 8349f31ec76c330c12ebdd7e5fb1d036175030a7 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 28 Jul 2023 19:11:15 +0100
Subject: Store bound variable names in typed block node

---
 .../org/shedlang/compiler/ast/typed/TypedBlockNode.java  |  6 ++++++
 .../compiler/ast/typed/TypedFunctionDefinitionNode.java  |  3 ++-
 .../compiler/typechecker/EnvironmentBuilder.java         |  6 ++++++
 .../org/shedlang/compiler/typechecker/TypeChecker.java   | 16 +++++++++-------
 4 files changed, 23 insertions(+), 8 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedBlockNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedBlockNode.java
index 5c0c8435..9753f974 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedBlockNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedBlockNode.java
@@ -7,8 +7,14 @@ import org.shedlang.compiler.util.Lists;
 
 import java.util.List;
 
+/**
+ * @param boundVariableNames The names of variables that are bound in the
+ *                           block's scope, not including any children scopes
+ *                           such as the bodies of <code>if</code> expressions.
+ */
 public record TypedBlockNode(
     List<? extends TypedFunctionStatementNode> statements,
+    List<String> boundVariableNames,
     Source source
 ) implements TypedNode {
     public TypedFunctionStatementBehaviour behaviour() {
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 2b14e345..b450158b 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionDefinitionNode.java
@@ -6,6 +6,7 @@ import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.sources.Sources;
 import org.shedlang.compiler.types.*;
 
+import java.util.List;
 import java.util.Optional;
 
 public record TypedFunctionDefinitionNode(
@@ -76,7 +77,7 @@ public record TypedFunctionDefinitionNode(
                 effect,
                 returnType,
                 freeVariables.build(),
-                new TypedBlockNode(body, Sources.NULL),
+                new TypedBlockNode(body, List.of(), Sources.NULL),
                 Sources.NULL
             );
         }
diff --git a/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java b/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
index 79c0a25e..53853305 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
@@ -6,6 +6,8 @@ import org.shedlang.compiler.ast.untyped.UntypedVariableDeclarationNode;
 import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.typechecker.errors.DuplicateVariableName;
 
+import java.util.List;
+
 public class EnvironmentBuilder {
     public static final EnvironmentBuilder EMPTY = new EnvironmentBuilder(Empty.map());
 
@@ -42,4 +44,8 @@ public class EnvironmentBuilder {
     public PMap<String, TypeCheckerContext.Variable> build() {
         return environment;
     }
+
+    public List<String> names() {
+        return environment.keySet().stream().toList();
+    }
 }
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 4ec4d5dc..bd02d88b 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -10,10 +10,7 @@ import org.shedlang.compiler.types.*;
 import org.shedlang.compiler.util.P;
 import org.shedlang.compiler.util.PCollectors;
 
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -186,6 +183,7 @@ public class TypeChecker {
 
     private static TypeCheckerResult<TypedBlockNode> typeCheckBlock(
         UntypedBlockNode untyped,
+        List<String> declaredVariableNames,
         TypeCheckerContext context
     ) {
         var typedStatementsResult = context.mapWithContext(
@@ -195,7 +193,11 @@ public class TypeChecker {
         var typedStatements = typedStatementsResult.value();
         context = typedStatementsResult.context();
 
-        var typed = new TypedBlockNode(typedStatements, untyped.source());
+        var typed = new TypedBlockNode(
+            typedStatements,
+            declaredVariableNames,
+            untyped.source()
+        );
 
         return context.toResult(typed);
     }
@@ -212,7 +214,7 @@ public class TypeChecker {
 
         context = context.enterBlock(bodyEnvironment.build());
 
-        var typedBodyResult = typeCheckBlock(untyped, context);
+        var typedBodyResult = typeCheckBlock(untyped, bodyEnvironment.names(), context);
         var typedBody = typedBodyResult.value();
         context = typedBodyResult.context();
 
@@ -450,7 +452,7 @@ public class TypeChecker {
             functionType.returnType()
         );
 
-        var bodyResult = typeCheckBlock(untyped.body(), context);
+        var bodyResult = typeCheckBlock(untyped.body(), bodyEnvironment.names(), context);
         var typedBody = bodyResult.value();
         context = bodyResult.context();
 
-- 
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