Make the fallthrough error more explicit

Add the target and effective addresses into the message, so it's more
clear how different they are.

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/xixanta/src/assembler.rs b/lib/xixanta/src/assembler.rs
index 136d416..326d97a 100644
--- a/lib/xixanta/src/assembler.rs
+++ b/lib/xixanta/src/assembler.rs
@@ -1057,7 +1057,10 @@ impl<'a> Assembler<'a> {
         if effective.address != target_address {
             return Err(Error {
                 line: pn.node.value.line,
-                message: String::from("statement does not fall through"),
+                message: format!(
+                    "statement expects to progress on '{}' (${:04X}), but the next address is ${:04X}",
+                    pn.node.value.value, target_address, effective.address,
+                ),
                 source: self.source_for(&pn.node),
                 expanded_from: pn.macro_context.clone(),
                 global: false,