Include unrecognised variant tag in error message

3 files changed, 25 insertions, 10 deletions

diff --git a/examples/16-transient-0/output/rust/src/gen/data/transient_0.rs b/examples/16-transient-0/output/rust/src/gen/data/transient_0.rs
index 67a6a11..0731126 100644
--- a/examples/16-transient-0/output/rust/src/gen/data/transient_0.rs
+++ b/examples/16-transient-0/output/rust/src/gen/data/transient_0.rs
@@ -250,7 +250,7 @@ pub fn decode_enum_with_variants(reader: &mut impl ::std::io::Read, shared_value
         0 => crate::data::EnumWithVariants::Zero,
         1 => crate::data::EnumWithVariants::One,
         2 => crate::data::EnumWithVariants::Two,
-        _ => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, "unrecognised variant tag for data.EnumWithVariants"))?,
+        tag => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, format!("unrecognised variant tag for data.EnumWithVariants: {}", tag)))?,
     })
 }
 
@@ -284,7 +284,7 @@ pub fn decode_sum_with_variants(reader: &mut impl ::std::io::Read, shared_values
     ::std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader, shared_values)? {
         0 => crate::data::SumWithVariants::VariantOne(crate::data::transient_0::decode_variant_one(reader, shared_values)?),
         1 => crate::data::SumWithVariants::VariantTwo(crate::data::transient_0::decode_variant_two(reader, shared_values)?),
-        _ => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, "unrecognised variant tag for data.SumWithVariants"))?,
+        tag => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, format!("unrecognised variant tag for data.SumWithVariants: {}", tag)))?,
     })
 }
 
@@ -326,7 +326,7 @@ pub fn decode_sum_with_boxed_variants(reader: &mut impl ::std::io::Read, shared_
     ::std::io::Result::Ok(match &crate::transient_0::decode_int_32(reader, shared_values)? {
         0 => crate::data::SumWithBoxedVariants::VariantOne(::std::boxed::Box::new(crate::data::transient_0::decode_variant_one(reader, shared_values)?)),
         1 => crate::data::SumWithBoxedVariants::VariantTwo(::std::boxed::Box::new(crate::data::transient_0::decode_variant_two(reader, shared_values)?)),
-        _ => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, "unrecognised variant tag for data.SumWithBoxedVariants"))?,
+        tag => ::std::result::Result::Err(::std::io::Error::new(::std::io::ErrorKind::InvalidData, format!("unrecognised variant tag for data.SumWithBoxedVariants: {}", tag)))?,
     })
 }
 
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
+                            )
+                        )
                     )
                 )
             )