fix: code gen tests now up to date using trace

fix: Formatter should take ErrorTerm and return "fail"
fix: fail with no reason should just return ErrorTerm

crates/aiken-lang/src/expr.rs

@@ -553,14 +553,15 @@ impl UntypedExpr {
     }
 
     pub fn fail(reason: Option<Self>, location: Span) -> Self {
-        UntypedExpr::Trace {
-            location,
-            kind: TraceKind::Error,
-            then: Box::new(UntypedExpr::ErrorTerm { location }),
-            text: Box::new(reason.unwrap_or_else(|| UntypedExpr::String {
+        if let Some(reason) = reason {
+            UntypedExpr::Trace {
                 location,
-                value: DEFAULT_ERROR_STR.to_string(),
-            })),
+                kind: TraceKind::Error,
+                then: Box::new(UntypedExpr::ErrorTerm { location }),
+                text: Box::new(reason),
+            }
+        } else {
+            UntypedExpr::ErrorTerm { location }
         }
     }
 

crates/aiken-lang/src/format.rs

@@ -860,7 +860,7 @@ impl<'comments> Formatter<'comments> {
                     .append(suffix)
             }
 
-            UntypedExpr::ErrorTerm { .. } => "error".to_doc(),
+            UntypedExpr::ErrorTerm { .. } => "fail".to_doc(),
 
             UntypedExpr::TraceIfFalse { value, .. } => self.trace_if_false(value),
         };

crates/aiken-lang/src/parser/expr/snapshots/fail_empty.snap

@@ -2,14 +2,6 @@
 source: crates/aiken-lang/src/parser/expr/fail_todo_trace.rs
 description: "Code:\n\nfail\n"
 ---
-Trace {
-    kind: Error,
+ErrorTerm {
     location: 0..4,
-    then: ErrorTerm {
-        location: 0..4,
-    },
-    text: String {
-        location: 0..4,
-        value: "aiken::error",
-    },
 }

crates/aiken-lang/src/parser/expr/when/snapshots/when_clause_solo_error.snap

@@ -24,16 +24,8 @@ When {
                 },
             ],
             guard: None,
-            then: Trace {
-                kind: Error,
+            then: ErrorTerm {
                 location: 28..32,
-                then: ErrorTerm {
-                    location: 28..32,
-                },
-                text: String {
-                    location: 28..32,
-                    value: "aiken::error",
-                },
             },
         },
     ],