From 942ca80a1f6d1cded5cb112dd347f8301567fe3f Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 9 Aug 2026 16:56:52 +0100
Subject: Add bounds to type params in Rust AST

---
 .../compiler/output/lang/rust/RustWriter.java      |  9 +++++++
 .../output/lang/rust/ast/RustTypeParam.java        | 30 +++++++++++++++++-----
 2 files changed, 33 insertions(+), 6 deletions(-)

(limited to 'src/main/java/org')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
index 7ae6bcf..72d17b7 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
@@ -283,6 +283,15 @@ public class RustWriter implements AutoCloseable {
 
     private void writeTypeParam(RustTypeParam typeParam) throws IOException {
         this.writeIdentifier(typeParam.name());
+
+        if (!typeParam.bounds().isEmpty()) {
+            this.writer.write(": ");
+            writeWithSeparator(
+                typeParam.bounds(),
+                this::writeType,
+                () -> this.writer.write(" + ")
+            );
+        }
     }
 
     // === Associated items ===
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustTypeParam.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustTypeParam.java
index db689f4..f7ce00a 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustTypeParam.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustTypeParam.java
@@ -6,25 +6,43 @@ package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
 // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam imports
 
 public record RustTypeParam(
-    org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name
+    org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name,
+    java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath> bounds
 ) {
     public static org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder arbitrary() {
-        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.arbitrary().build());
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.arbitrary().build(), java.util.List.of());
     }
 
     public record Builder(
-        org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name
+        org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name,
+        java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath> bounds
     ) {
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam build() {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam(name);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam(name, bounds);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder withName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name) {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name, bounds);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder withName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.Builder name) {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name.build());
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name.build(), bounds);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder withBounds(java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath> bounds) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name, bounds);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder addBound(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath bound) {
+            var bounds = new java.util.ArrayList<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath>(this.bounds);
+            bounds.add(bound);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name, bounds);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder addBound(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath.Builder bound) {
+            var bounds = new java.util.ArrayList<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustPath>(this.bounds);
+            bounds.add(bound.build());
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder(name, bounds);
         }
 
         // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustTypeParam.Builder body
-- 
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