Use type params in struct fields

1 files changed, 22 insertions, 4 deletions

diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 54a3722c..964a0000 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -3,6 +3,7 @@ package org.shedlang.compiler.typechecker;
 import org.shedlang.compiler.ast.typed.*;
 import org.shedlang.compiler.ast.untyped.*;
 import org.shedlang.compiler.sources.Source;
+import org.shedlang.compiler.sources.Sources;
 import org.shedlang.compiler.typechecker.errors.NoSuchFieldError;
 import org.shedlang.compiler.typechecker.errors.*;
 import org.shedlang.compiler.typechecker.typesets.TypeSetTypeLevelValue;
@@ -1440,6 +1441,26 @@ public class TypeChecker {
 
             @Override
             public TypeCheckerContext defineTypes(TypeCheckerContext context) {
+                var typeOrConstructor = (TypeOrConstructor<StructType>) context.getLexicalState(
+                    TypeOrConstructor.class,
+                    untyped.name()
+                );
+
+                var environment = EnvironmentBuilder.EMPTY;
+
+                if (typeOrConstructor instanceof TypeOrConstructor.Constructor<StructType> constructor) {
+                    for (var param : constructor.value().params()) {
+                        // TODO: proper source
+                        environment = environment.add(
+                            param.name(),
+                            Variable.defined(Types.metaType(param), VariableType.CONSTANT),
+                            Sources.NULL
+                        );
+                    }
+                }
+
+                context = context.enterBlock(environment.build());
+
                 var typedFieldNodes = new ArrayList<TypedStructFieldDefinitionNode>();
                 var fieldInfosBuilder = FieldsInfo.builder();
 
@@ -1453,10 +1474,7 @@ public class TypeChecker {
                     fieldInfosBuilder = fieldInfosBuilder.addField(untypedField.name(), typedFieldNode.type().value());
                 }
 
-                var typeOrConstructor = (TypeOrConstructor<StructType>) context.getLexicalState(
-                    TypeOrConstructor.class,
-                    untyped.name()
-                );
+                context = context.exit();
 
                 context = context.addStructTypeInfo(
                     typeOrConstructor.toType(),