Include unrecognised variant tag in error message

2 files changed, 22 insertions, 7 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
index 65bfdfe..5c4c22c 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
@@ -653,6 +653,7 @@ public class JavaTransient0Generator implements Generator {
                 enumDefinition.type(),
                 new JavaBlock(Stream.concat(
                     generateDecode(ordinal, NativeTypes.INT_32, context).stream(),
+                    // TODO: handle ordinal not in array
                     Stream.of(new JavaReturn(new JavaArrayAccess(
                         new JavaRef(enumValues),
                         new JavaRef(ordinal)
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
index 354dfb5..46e0a5c 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
@@ -441,8 +441,11 @@ public class RustTransient0Generator implements Generator {
             .collect(toArrayList());
 
         decodeMatchArms.add(new RustMatchArm(
-            new RustWildcardPattern(),
-            new RustTryPropagationExpression(generateUnrecognisedVariantResult(enumDefinition.type()))
+            new RustIdentifierPattern(RustIdentifier.of("tag")),
+            new RustTryPropagationExpression(generateUnrecognisedVariantResult(
+                enumDefinition.type(),
+                RustPath.of("tag")
+            ))
         ));
 
         return generateDecodeFunction(
@@ -584,8 +587,11 @@ public class RustTransient0Generator implements Generator {
             .collect(toArrayList());
 
         decodeMatchArms.add(new RustMatchArm(
-            new RustWildcardPattern(),
-            new RustTryPropagationExpression(generateUnrecognisedVariantResult(sumDefinition.type()))
+            new RustIdentifierPattern(RustIdentifier.of("tag")),
+            new RustTryPropagationExpression(generateUnrecognisedVariantResult(
+                sumDefinition.type(),
+                RustPath.of("tag")
+            ))
         ));
 
         return generateDecodeFunction(
@@ -1347,7 +1353,10 @@ public class RustTransient0Generator implements Generator {
         );
     }
 
-    private static RustCallExpression generateUnrecognisedVariantResult(Type type) {
+    private static RustCallExpression generateUnrecognisedVariantResult(
+        Type type,
+        RustExpression tag
+    ) {
         return new RustCallExpression(
             RustTypes.RESULT_ERR,
             List.of(
@@ -1355,8 +1364,13 @@ public class RustTransient0Generator implements Generator {
                     RustTypes.IO_ERROR.addSegment(RustPathSegment.of("new")),
                     List.of(
                         RustTypes.IO_ERROR_KIND_INVALID_DATA,
-                        // TODO: include variant tag
-                        new RustStringLiteral("unrecognised variant tag for " + type.describe())
+                        new RustCallExpression(
+                            RustPath.of("format!"),
+                            List.of(
+                                new RustStringLiteral("unrecognised variant tag for " + type.describe() + ": {}"),
+                                tag
+                            )
+                        )
                     )
                 )
             )