Rework 'compact' mode for traces

- Trace-if-false are now completely discarded in compact mode.

  - Only the label (i.e. first trace argument) is preserved.

  - When compiling with tracing _compact_, the first label MUST unify to
    a string. This shouldn't be an issue generally speaking and would
    enforce that traces follow the pattern

    ```
    label: arg_0[, arg_1, ..., arg_n]
    ```

  Note that what isn't obvious with these changes is that we now support
  what the "emit" keyword was trying to achieve; as we compile now with
  user-defined traces only, and in compact mode to only keep event
  labels in the final contract; while allowing larger payloads with
  verbose tracing.

crates/aiken-lang/src/ast.rs

@@ -1957,6 +1957,10 @@ pub enum TraceLevel {
 }
 
 impl Tracing {
+    pub fn verbose() -> Self {
+        Tracing::All(TraceLevel::Verbose)
+    }
+
     pub fn silent() -> Self {
         Tracing::All(TraceLevel::Silent)
     }

crates/aiken-lang/src/tests/check.rs

@@ -18,6 +18,7 @@ fn check_module(
     ast: UntypedModule,
     extra: Vec<(String, UntypedModule)>,
     kind: ModuleKind,
+    tracing: Tracing,
 ) -> Result<(Vec<Warning>, TypedModule), (Vec<Warning>, Error)> {
     let id_gen = IdGenerator::new();
 
@@ -47,7 +48,7 @@ fn check_module(
         kind,
         "test/project",
         &module_types,
-        Tracing::All(TraceLevel::Verbose),
+        tracing,
         &mut warnings,
     );
 
@@ -57,20 +58,27 @@ fn check_module(
 }
 
 fn check(ast: UntypedModule) -> Result<(Vec<Warning>, TypedModule), (Vec<Warning>, Error)> {
-    check_module(ast, Vec::new(), ModuleKind::Lib)
+    check_module(ast, Vec::new(), ModuleKind::Lib, Tracing::verbose())
+}
+
+fn check_with_verbosity(
+    ast: UntypedModule,
+    level: TraceLevel,
+) -> Result<(Vec<Warning>, TypedModule), (Vec<Warning>, Error)> {
+    check_module(ast, Vec::new(), ModuleKind::Lib, Tracing::All(level))
 }
 
 fn check_with_deps(
     ast: UntypedModule,
     extra: Vec<(String, UntypedModule)>,
 ) -> Result<(Vec<Warning>, TypedModule), (Vec<Warning>, Error)> {
-    check_module(ast, extra, ModuleKind::Lib)
+    check_module(ast, extra, ModuleKind::Lib, Tracing::verbose())
 }
 
 fn check_validator(
     ast: UntypedModule,
 ) -> Result<(Vec<Warning>, TypedModule), (Vec<Warning>, Error)> {
-    check_module(ast, Vec::new(), ModuleKind::Validator)
+    check_module(ast, Vec::new(), ModuleKind::Validator, Tracing::verbose())
 }
 
 #[test]
@@ -1288,8 +1296,32 @@ fn trace_non_strings() {
             True
         }
     "#;
+    assert!(check(parse(source_code)).is_ok())
+}
+
+#[test]
+fn trace_string_label_compact() {
+    let source_code = r#"
+        test foo() {
+            trace @"foo": [1,2,3]
+            True
+        }
+    "#;
+
+    assert!(check(parse(source_code)).is_ok())
+}
+
+#[test]
+fn trace_non_string_label_compact() {
+    let source_code = r#"
+        test foo() {
+            trace(14 + 42)
+            True
+        }
+    "#;
+
     assert!(matches!(
-        check(parse(source_code)),
+        check_with_verbosity(parse(source_code), TraceLevel::Compact),
         Err((_, Error::CouldNotUnify { .. }))
     ))
 }

crates/aiken-lang/src/tipo/expr.rs

@@ -24,7 +24,6 @@ use crate::{
     },
     expr::{FnStyle, TypedExpr, UntypedExpr},
     format,
-    line_numbers::LineNumbers,
     tipo::{fields::FieldMap, DefaultFunction, PatternConstructor, TypeVar},
     IdGenerator,
 };
@@ -41,7 +40,6 @@ pub(crate) fn infer_function(
     module_name: &str,
     hydrators: &mut HashMap<String, Hydrator>,
     environment: &mut Environment<'_>,
-    lines: &LineNumbers,
     tracing: Tracing,
 ) -> Result<Function<Rc<Type>, TypedExpr, TypedArg>, Error> {
     if let Some(typed_fun) = environment.inferred_functions.get(&fun.name) {
@@ -122,7 +120,7 @@ pub(crate) fn infer_function(
         .remove(name)
         .unwrap_or_else(|| panic!("Could not find hydrator for fn {name}"));
 
-    let mut expr_typer = ExprTyper::new(environment, lines, tracing);
+    let mut expr_typer = ExprTyper::new(environment, tracing);
     expr_typer.hydrator = hydrator;
     expr_typer.not_yet_inferred = BTreeSet::from_iter(hydrators.keys().cloned());
 
@@ -155,12 +153,11 @@ pub(crate) fn infer_function(
             environment.current_module,
             hydrators,
             environment,
-            lines,
             tracing,
         )?;
 
         // Then, try again the entire function definition.
-        return infer_function(fun, module_name, hydrators, environment, lines, tracing);
+        return infer_function(fun, module_name, hydrators, environment, tracing);
     }
 
     let (arguments, body, return_type) = inferred?;
@@ -223,8 +220,6 @@ pub(crate) fn infer_function(
 
 #[derive(Debug)]
 pub(crate) struct ExprTyper<'a, 'b> {
-    pub(crate) lines: &'a LineNumbers,
-
     pub(crate) environment: &'a mut Environment<'b>,
 
     // We tweak the tracing behavior during type-check. Traces are either kept or left out of the
@@ -244,18 +239,13 @@ pub(crate) struct ExprTyper<'a, 'b> {
 }
 
 impl<'a, 'b> ExprTyper<'a, 'b> {
-    pub fn new(
-        environment: &'a mut Environment<'b>,
-        lines: &'a LineNumbers,
-        tracing: Tracing,
-    ) -> Self {
+    pub fn new(environment: &'a mut Environment<'b>, tracing: Tracing) -> Self {
         Self {
             hydrator: Hydrator::new(),
             not_yet_inferred: BTreeSet::new(),
             environment,
             tracing,
             ungeneralised_function_used: false,
-            lines,
         }
     }
 
@@ -681,25 +671,16 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
                         .to_pretty_string(999)
                 ),
             }),
-            TraceLevel::Compact => Some(TypedExpr::String {
-                location,
-                tipo: string(),
-                value: self
-                    .lines
-                    .line_and_column_number(location.start)
-                    .expect("Spans are within bounds.")
-                    .to_string(),
-            }),
-            TraceLevel::Silent => None,
+            TraceLevel::Compact | TraceLevel::Silent => None,
         };
 
         let typed_value = self.infer(value)?;
 
         self.unify(bool(), typed_value.tipo(), typed_value.location(), false)?;
 
-        match self.tracing.trace_level(false) {
-            TraceLevel::Silent => Ok(typed_value),
-            TraceLevel::Verbose | TraceLevel::Compact => Ok(TypedExpr::If {
+        match text {
+            None => Ok(typed_value),
+            Some(text) => Ok(TypedExpr::If {
                 location,
                 branches: vec1::vec1![IfBranch {
                     condition: typed_value,
@@ -710,7 +691,7 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
                 final_else: Box::new(TypedExpr::Trace {
                     location,
                     tipo: bool(),
-                    text: Box::new(text.expect("TraceLevel::Silent excluded from pattern-guard")),
+                    text: Box::new(text),
                     then: Box::new(var_false),
                 }),
                 tipo: bool(),
@@ -2426,29 +2407,11 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
         label: UntypedExpr,
         arguments: Vec<UntypedExpr>,
     ) -> Result<TypedExpr, Error> {
-        let label = self.infer_trace_arg(label)?;
-
         let typed_arguments = arguments
             .into_iter()
             .map(|arg| self.infer_trace_arg(arg))
             .collect::<Result<Vec<_>, Error>>()?;
 
-        let text = if typed_arguments.is_empty() {
-            label
-        } else {
-            let delimiter = |ix| TypedExpr::String {
-                location: Span::empty(),
-                tipo: string(),
-                value: if ix == 0 { ": " } else { ", " }.to_string(),
-            };
-            typed_arguments
-                .into_iter()
-                .enumerate()
-                .fold(label, |text, (ix, arg)| {
-                    append_string_expr(append_string_expr(text, delimiter(ix)), arg)
-                })
-        };
-
         let then = self.infer(then)?;
         let tipo = then.tipo();
 
@@ -2461,26 +2424,42 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
 
         match self.tracing.trace_level(false) {
             TraceLevel::Silent => Ok(then),
-            TraceLevel::Compact => Ok(TypedExpr::Trace {
-                location,
-                tipo,
-                then: Box::new(then),
-                text: Box::new(TypedExpr::String {
+            TraceLevel::Compact => {
+                let text = self.infer(label)?;
+                self.unify(string(), text.tipo(), text.location(), false)?;
+                Ok(TypedExpr::Trace {
                     location,
-                    tipo: string(),
-                    value: self
-                        .lines
-                        .line_and_column_number(location.start)
-                        .expect("Spans are within bounds.")
-                        .to_string(),
-                }),
-            }),
-            TraceLevel::Verbose => Ok(TypedExpr::Trace {
-                location,
-                tipo,
-                then: Box::new(then),
-                text: Box::new(text),
-            }),
+                    tipo,
+                    then: Box::new(then),
+                    text: Box::new(text),
+                })
+            }
+            TraceLevel::Verbose => {
+                let label = self.infer_trace_arg(label)?;
+
+                let text = if typed_arguments.is_empty() {
+                    label
+                } else {
+                    let delimiter = |ix| TypedExpr::String {
+                        location: Span::empty(),
+                        tipo: string(),
+                        value: if ix == 0 { ": " } else { ", " }.to_string(),
+                    };
+                    typed_arguments
+                        .into_iter()
+                        .enumerate()
+                        .fold(label, |text, (ix, arg)| {
+                            append_string_expr(append_string_expr(text, delimiter(ix)), arg)
+                        })
+                };
+
+                Ok(TypedExpr::Trace {
+                    location,
+                    tipo,
+                    then: Box::new(then),
+                    text: Box::new(text),
+                })
+            }
         }
     }
 

crates/aiken-lang/src/tipo/infer.rs

@@ -13,7 +13,6 @@ use crate::{
     },
     builtins,
     builtins::{fuzzer, generic_var},
-    line_numbers::LineNumbers,
     tipo::{expr::infer_function, Span, Type, TypeVar},
     IdGenerator,
 };
@@ -86,14 +85,8 @@ impl UntypedModule {
         }
 
         for def in consts.into_iter().chain(not_consts) {
-            let definition = infer_definition(
-                def,
-                &module_name,
-                &mut hydrators,
-                &mut environment,
-                &self.lines,
-                tracing,
-            )?;
+            let definition =
+                infer_definition(def, &module_name, &mut hydrators, &mut environment, tracing)?;
 
             definitions.push(definition);
         }
@@ -162,7 +155,6 @@ fn infer_definition(
     module_name: &String,
     hydrators: &mut HashMap<String, Hydrator>,
     environment: &mut Environment<'_>,
-    lines: &LineNumbers,
     tracing: Tracing,
 ) -> Result<TypedDefinition, Error> {
     match def {
@@ -171,7 +163,6 @@ fn infer_definition(
             module_name,
             hydrators,
             environment,
-            lines,
             tracing,
         )?)),
 
@@ -228,7 +219,7 @@ fn infer_definition(
                 }
 
                 let mut typed_fun =
-                    infer_function(&fun, module_name, hydrators, environment, lines, tracing)?;
+                    infer_function(&fun, module_name, hydrators, environment, tracing)?;
 
                 if !typed_fun.return_type.is_bool() {
                     return Err(Error::ValidatorMustReturnBool {
@@ -267,14 +258,8 @@ fn infer_definition(
                         let params = params.into_iter().chain(other.arguments);
                         other.arguments = params.collect();
 
-                        let mut other_typed_fun = infer_function(
-                            &other,
-                            module_name,
-                            hydrators,
-                            environment,
-                            lines,
-                            tracing,
-                        )?;
+                        let mut other_typed_fun =
+                            infer_function(&other, module_name, hydrators, environment, tracing)?;
 
                         if !other_typed_fun.return_type.is_bool() {
                             return Err(Error::ValidatorMustReturnBool {
@@ -338,8 +323,7 @@ fn infer_definition(
                         });
                     }
 
-                    let typed_via =
-                        ExprTyper::new(environment, lines, tracing).infer(arg.via.clone())?;
+                    let typed_via = ExprTyper::new(environment, tracing).infer(arg.via.clone())?;
 
                     let hydrator: &mut Hydrator = hydrators.get_mut(&f.name).unwrap();
 
@@ -404,14 +388,7 @@ fn infer_definition(
                 None => Ok((None, None)),
             }?;
 
-            let typed_f = infer_function(
-                &f.into(),
-                module_name,
-                hydrators,
-                environment,
-                lines,
-                tracing,
-            )?;
+            let typed_f = infer_function(&f.into(), module_name, hydrators, environment, tracing)?;
 
             environment.unify(
                 typed_f.return_type.clone(),
@@ -629,7 +606,7 @@ fn infer_definition(
             tipo: _,
         }) => {
             let typed_expr =
-                ExprTyper::new(environment, lines, tracing).infer_const(&annotation, *value)?;
+                ExprTyper::new(environment, tracing).infer_const(&annotation, *value)?;
 
             let tipo = typed_expr.tipo();