[fine] Many test improvements, error improvements

- Check for more error conditions
- Move to more definitive error assertions
- Simpler error messages in some cases
- Test more conditions more thoroughly, revisit old tests

fine/src/compiler.rs

@@ -308,7 +308,6 @@ fn compile_literal(c: &mut Compiler, t: TreeRef, tr: &Tree) -> CR {
             Instruction::PushFalse
         }),
         Type::String => {
-            // TODO: Interpret string here make good!
             let mut result = String::new();
             let mut input = tok.as_str().chars();
             while let Some(ch) = input.next() {
@@ -514,7 +513,6 @@ fn compile_identifier_expression(c: &mut Compiler, t: TreeRef, tree: &Tree) -> O
 }
 
 fn compile_load_declaration(c: &mut Compiler, t: TreeRef, declaration: &Declaration) -> CR {
-    // TODO: Load function declaration. :P
     let instruction = match declaration {
         Declaration::Variable {
             location, index, ..
@@ -555,6 +553,8 @@ fn compile_load_declaration(c: &mut Compiler, t: TreeRef, declaration: &Declarat
             Instruction::LoadFunction(index)
         }
         Declaration::ExternFunction { id, .. } => Instruction::LoadExternFunction(id.id()),
+
+        // There is no universe where it's possible to use a class as a variable.
         Declaration::Class { .. } => Instruction::Panic,
     };