Revise documentation.

src/api/limits.rs

@@ -6,23 +6,20 @@ use std::num::{NonZeroU64, NonZeroUsize};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
+#[cfg(debug_assertions)]
 pub mod default_limits {
-    #[cfg(debug_assertions)]
     #[cfg(not(feature = "no_function"))]
     pub const MAX_CALL_STACK_DEPTH: usize = 8;
-    #[cfg(debug_assertions)]
     pub const MAX_EXPR_DEPTH: usize = 32;
     #[cfg(not(feature = "no_function"))]
-    #[cfg(debug_assertions)]
     pub const MAX_FUNCTION_EXPR_DEPTH: usize = 16;
-
+}
-    #[cfg(not(debug_assertions))]
+#[cfg(not(debug_assertions))]
+pub mod default_limits {
     #[cfg(not(feature = "no_function"))]
     pub const MAX_CALL_STACK_DEPTH: usize = 64;
-    #[cfg(not(debug_assertions))]
     pub const MAX_EXPR_DEPTH: usize = 64;
     #[cfg(not(feature = "no_function"))]
-    #[cfg(not(debug_assertions))]
     pub const MAX_FUNCTION_EXPR_DEPTH: usize = 32;
 }
 
@@ -55,7 +52,7 @@ pub struct Limits {
     #[cfg(not(feature = "no_module"))]
     pub max_modules: usize,
     /// Maximum length of a [string][crate::ImmutableString].
-    pub max_string_size: Option<NonZeroUsize>,
+    pub max_string_len: Option<NonZeroUsize>,
     /// Maximum length of an [array][crate::Array].
     ///
     /// Not available under `no_index`.
@@ -83,7 +80,7 @@ impl Limits {
             max_operations: None,
             #[cfg(not(feature = "no_module"))]
             max_modules: usize::MAX,
-            max_string_size: None,
+            max_string_len: None,
             #[cfg(not(feature = "no_index"))]
             max_array_size: None,
             #[cfg(not(feature = "no_object"))]
@@ -104,7 +101,7 @@ impl Engine {
     /// Is there a data size limit set?
     #[inline(always)]
     pub(crate) const fn has_data_size_limit(&self) -> bool {
-        self.limits.max_string_size.is_some()
+        self.limits.max_string_len.is_some()
             || {
                 #[cfg(not(feature = "no_index"))]
                 {
@@ -222,19 +219,19 @@ impl Engine {
         #[cfg(feature = "no_function")]
         return 0;
     }
-    /// Set the maximum length of [strings][crate::ImmutableString] (0 for unlimited).
+    /// Set the maximum length, in bytes, of [strings][crate::ImmutableString] (0 for unlimited).
     ///
     /// Not available under `unchecked`.
     #[inline(always)]
-    pub fn set_max_string_size(&mut self, max_size: usize) -> &mut Self {
+    pub fn set_max_string_size(&mut self, max_len: usize) -> &mut Self {
-        self.limits.max_string_size = NonZeroUsize::new(max_size);
+        self.limits.max_string_len = NonZeroUsize::new(max_len);
         self
     }
-    /// The maximum length of [strings][crate::ImmutableString] (0 for unlimited).
+    /// The maximum length, in bytes, of [strings][crate::ImmutableString] (0 for unlimited).
     #[inline]
     #[must_use]
     pub const fn max_string_size(&self) -> usize {
-        match self.limits.max_string_size {
+        match self.limits.max_string_len {
             Some(n) => n.get(),
             None => 0,
         }

src/api/limits_unchecked.rs

@@ -1,3 +1,4 @@
+//! Placeholder settings for [`Engine`]'s limitations.
 #![cfg(feature = "unchecked")]
 
 use crate::Engine;
@@ -5,7 +6,7 @@ use crate::Engine;
 impl Engine {
     /// The maximum levels of function calls allowed for a script.
     ///
-    /// Always returns [`usize::MAX`] under `unchecked`.
+    /// Always returns [`usize::MAX`].
     #[inline(always)]
     #[must_use]
     pub const fn max_call_levels(&self) -> usize {
@@ -13,7 +14,7 @@ impl Engine {
     }
     /// The maximum number of operations allowed for a script to run (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_operations(&self) -> u64 {
@@ -21,7 +22,7 @@ impl Engine {
     }
     /// The maximum number of imported [modules][crate::Module] allowed for a script.
     ///
-    /// Always returns [`usize::MAX`] under `unchecked`.
+    /// Always returns [`usize::MAX`].
     #[inline(always)]
     #[must_use]
     pub const fn max_modules(&self) -> usize {
@@ -29,7 +30,7 @@ impl Engine {
     }
     /// The depth limit for expressions (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_expr_depth(&self) -> usize {
@@ -37,7 +38,7 @@ impl Engine {
     }
     /// The depth limit for expressions in functions (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_function_expr_depth(&self) -> usize {
@@ -45,7 +46,7 @@ impl Engine {
     }
     /// The maximum length of [strings][crate::ImmutableString] (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_string_size(&self) -> usize {
@@ -53,7 +54,7 @@ impl Engine {
     }
     /// The maximum length of [arrays][crate::Array] (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_array_size(&self) -> usize {
@@ -61,7 +62,7 @@ impl Engine {
     }
     /// The maximum size of [object maps][crate::Map] (0 for unlimited).
     ///
-    /// Always returns zero under `unchecked`.
+    /// Always returns zero.
     #[inline(always)]
     #[must_use]
     pub const fn max_map_size(&self) -> usize {

src/eval/data_check.rs

@@ -80,7 +80,7 @@ impl Engine {
     ) -> RhaiResultOf<()> {
         if self
             .limits
-            .max_string_size
+            .max_string_len
             .map_or(false, |max| s > max.get())
         {
             return Err(

src/eval/stmt.rs

@@ -501,13 +501,15 @@ impl Engine {
                 // 2) Global modules - packages
                 // 3) Imported modules - functions marked with global namespace
                 // 4) Global sub-modules - functions marked with global namespace
-                let func = self
+                let iter_func = self
                     .global_modules
                     .iter()
                     .find_map(|m| m.get_iter(iter_type));
 
                 #[cfg(not(feature = "no_module"))]
-                let func = func.or_else(|| global.get_iter(iter_type)).or_else(|| {
+                let iter_func = iter_func
+                    .or_else(|| global.get_iter(iter_type))
+                    .or_else(|| {
                         self.global_sub_modules
                             .as_deref()
                             .into_iter()
@@ -515,7 +517,7 @@ impl Engine {
                             .find_map(|(_, m)| m.get_qualified_iter(iter_type))
                     });
 
-                let func = func.ok_or_else(|| ERR::ErrorFor(expr.start_position()))?;
+                let iter_func = iter_func.ok_or_else(|| ERR::ErrorFor(expr.start_position()))?;
 
                 // Restore scope at end of statement
                 let orig_scope_len = scope.len();
@@ -536,7 +538,7 @@ impl Engine {
 
                 let mut result = Dynamic::UNIT;
 
-                for (x, iter_value) in func(iter_obj).enumerate() {
+                for (x, iter_value) in iter_func(iter_obj).enumerate() {
                     // Increment counter
                     if counter_index < usize::MAX {
                         // As the variable increments from 0, this should always work
@@ -604,10 +606,7 @@ impl Engine {
             Stmt::TryCatch(x, ..) => {
                 let TryCatchBlock {
                     try_block,
-                    catch_var:
+                    catch_var,
-                        Ident {
-                            name: catch_var, ..
-                        },
                     catch_block,
                 } = &**x;
 
@@ -659,7 +658,7 @@ impl Engine {
                             });
 
                         if !catch_var.is_empty() {
-                            scope.push(catch_var.clone(), err_value);
+                            scope.push(catch_var.name.clone(), err_value);
                         }
 
                         self.eval_stmt_block(global, caches, scope, this_ptr, catch_block, true)
@@ -768,7 +767,7 @@ impl Engine {
 
                 #[cfg(not(feature = "no_module"))]
                 if let Some(alias) = _alias {
-                    scope.add_alias_by_index(scope.len() - 1, alias.name.as_str().into());
+                    scope.add_alias_by_index(scope.len() - 1, alias.as_str().into());
                 }
 
                 Ok(Dynamic::UNIT)

src/eval/target.rs

@@ -186,6 +186,7 @@ impl<'a> Target<'a> {
             Self::RefMut(r) => r.is_shared(),
             Self::SharedValue { .. } => true,
             Self::TempValue(value) => value.is_shared(),
+            #[cfg(not(feature = "no_index"))]
             Self::Bit { .. }
             | Self::BitField { .. }
             | Self::BlobByte { .. }

src/func/callable_function.rs

@@ -204,16 +204,16 @@ impl CallableFunction {
 #[cfg(not(feature = "no_function"))]
 impl From<crate::ast::ScriptFnDef> for CallableFunction {
     #[inline(always)]
-    fn from(_func: crate::ast::ScriptFnDef) -> Self {
+    fn from(func: crate::ast::ScriptFnDef) -> Self {
-        Self::Script(_func.into())
+        Self::Script(func.into())
     }
 }
 
 #[cfg(not(feature = "no_function"))]
 impl From<Shared<crate::ast::ScriptFnDef>> for CallableFunction {
     #[inline(always)]
-    fn from(_func: Shared<crate::ast::ScriptFnDef>) -> Self {
+    fn from(func: Shared<crate::ast::ScriptFnDef>) -> Self {
-        Self::Script(_func)
+        Self::Script(func)
     }
 }
 

src/parser.rs

@@ -1464,7 +1464,7 @@ impl Engine {
                 // Restore the strings interner by swapping it back
                 std::mem::swap(state.interned_strings, new_state.interned_strings);
 
-                let (expr, func) = result?;
+                let (expr, f) = result?;
 
                 #[cfg(not(feature = "no_closure"))]
                 new_state
@@ -1490,8 +1490,8 @@ impl Engine {
                         }
                     })?;
 
-                let hash_script = calc_fn_hash(None, &func.name, func.params.len());
+                let hash_script = calc_fn_hash(None, &f.name, f.params.len());
-                lib.insert(hash_script, func.into());
+                lib.insert(hash_script, f.into());
 
                 expr
             }
@@ -2170,42 +2170,42 @@ impl Engine {
             )),
             // lhs.nnn::func(...) - syntax error
             #[cfg(not(feature = "no_module"))]
-            (.., Expr::FnCall(func, ..)) if func.is_qualified() => {
+            (.., Expr::FnCall(f, ..)) if f.is_qualified() => {
-                Err(PERR::PropertyExpected.into_err(func.namespace.position()))
+                Err(PERR::PropertyExpected.into_err(f.namespace.position()))
             }
             // lhs.Fn() or lhs.eval()
-            (.., Expr::FnCall(func, func_pos))
+            (.., Expr::FnCall(f, func_pos))
-                if func.args.is_empty()
+                if f.args.is_empty()
                     && [crate::engine::KEYWORD_FN_PTR, crate::engine::KEYWORD_EVAL]
-                        .contains(&func.name.as_str()) =>
+                        .contains(&f.name.as_str()) =>
             {
                 let err_msg = format!(
                     "'{}' should not be called in method style. Try {}(...);",
-                    func.name, func.name
+                    f.name, f.name
                 );
-                Err(LexError::ImproperSymbol(func.name.to_string(), err_msg).into_err(func_pos))
+                Err(LexError::ImproperSymbol(f.name.to_string(), err_msg).into_err(func_pos))
             }
             // lhs.func!(...)
-            (.., Expr::FnCall(func, func_pos)) if func.capture_parent_scope => {
+            (.., Expr::FnCall(f, func_pos)) if f.capture_parent_scope => {
                 Err(PERR::MalformedCapture(
                     "method-call style does not support running within the caller's scope".into(),
                 )
                 .into_err(func_pos))
             }
             // lhs.func(...)
-            (lhs, Expr::FnCall(mut func, func_pos)) => {
+            (lhs, Expr::FnCall(mut f, func_pos)) => {
                 // Recalculate hash
-                func.hashes = if is_valid_function_name(&func.name) {
+                f.hashes = if is_valid_function_name(&f.name) {
                     FnCallHashes::from_all(
                         #[cfg(not(feature = "no_function"))]
-                        calc_fn_hash(None, &func.name, func.args.len()),
+                        calc_fn_hash(None, &f.name, f.args.len()),
-                        calc_fn_hash(None, &func.name, func.args.len() + 1),
+                        calc_fn_hash(None, &f.name, f.args.len() + 1),
                     )
                 } else {
-                    FnCallHashes::from_native(calc_fn_hash(None, &func.name, func.args.len() + 1))
+                    FnCallHashes::from_native(calc_fn_hash(None, &f.name, f.args.len() + 1))
                 };
 
-                let rhs = Expr::MethodCall(func, func_pos);
+                let rhs = Expr::MethodCall(f, func_pos);
                 Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
             }
             // lhs.dot_lhs.dot_rhs or lhs.dot_lhs[idx_rhs]
@@ -2224,8 +2224,8 @@ impl Engine {
                     }
                     // lhs.module::func().dot_rhs or lhs.module::func()[idx_rhs] - syntax error
                     #[cfg(not(feature = "no_module"))]
-                    Expr::FnCall(func, ..) if func.is_qualified() => {
+                    Expr::FnCall(f, ..) if f.is_qualified() => {
-                        Err(PERR::PropertyExpected.into_err(func.namespace.position()))
+                        Err(PERR::PropertyExpected.into_err(f.namespace.position()))
                     }
                     // lhs.id.dot_rhs or lhs.id[idx_rhs]
                     Expr::Variable(..) | Expr::Property(..) => {
@@ -2243,24 +2243,20 @@ impl Engine {
                         Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
                     }
                     // lhs.func().dot_rhs or lhs.func()[idx_rhs]
-                    Expr::FnCall(mut func, func_pos) => {
+                    Expr::FnCall(mut f, func_pos) => {
                         // Recalculate hash
-                        func.hashes = if is_valid_function_name(&func.name) {
+                        f.hashes = if is_valid_function_name(&f.name) {
                             FnCallHashes::from_all(
                                 #[cfg(not(feature = "no_function"))]
-                                calc_fn_hash(None, &func.name, func.args.len()),
+                                calc_fn_hash(None, &f.name, f.args.len()),
-                                calc_fn_hash(None, &func.name, func.args.len() + 1),
+                                calc_fn_hash(None, &f.name, f.args.len() + 1),
                             )
                         } else {
-                            FnCallHashes::from_native(calc_fn_hash(
+                            FnCallHashes::from_native(calc_fn_hash(None, &f.name, f.args.len() + 1))
-                                None,
-                                &func.name,
-                                func.args.len() + 1,
-                            ))
                         };
 
                         let new_lhs = BinaryExpr {
-                            lhs: Expr::MethodCall(func, func_pos),
+                            lhs: Expr::MethodCall(f, func_pos),
                             rhs: x.rhs,
                         }
                         .into();
@@ -3303,7 +3299,7 @@ impl Engine {
                             max_expr_depth: self.max_function_expr_depth(),
                         };
 
-                        let func = self.parse_fn(
+                        let f = self.parse_fn(
                             input,
                             new_state,
                             lib,
@@ -3312,22 +3308,21 @@ impl Engine {
                             #[cfg(not(feature = "no_function"))]
                             #[cfg(feature = "metadata")]
                             comments,
-                        );
+                        )?;
 
                         // Restore parse state
-                        let func = func?;
 
-                        let hash = calc_fn_hash(None, &func.name, func.params.len());
+                        let hash = calc_fn_hash(None, &f.name, f.params.len());
 
                         if !lib.is_empty() && lib.contains_key(&hash) {
                             return Err(PERR::FnDuplicatedDefinition(
-                                func.name.to_string(),
+                                f.name.to_string(),
-                                func.params.len(),
+                                f.params.len(),
                             )
                             .into_err(pos));
                         }
 
-                        lib.insert(hash, func.into());
+                        lib.insert(hash, f.into());
 
                         Ok(Stmt::Noop(pos))
                     }

src/tokenizer.rs

@@ -852,7 +852,7 @@ impl From<Token> for String {
 #[derive(Debug, Clone, Eq, PartialEq, Default)]
 pub struct TokenizeState {
     /// Maximum length of a string.
-    pub max_string_size: Option<NonZeroUsize>,
+    pub max_string_len: Option<NonZeroUsize>,
     /// Can the next token be a unary operator?
     pub next_token_cannot_be_unary: bool,
     /// Shared object to allow controlling the tokenizer externally.
@@ -879,6 +879,18 @@ pub trait InputStream {
     fn peek_next(&mut self) -> Option<char>;
 }
 
+/// Return error if the string is longer than the maximum length.
+#[inline]
+fn ensure_string_len_within_limit(max: Option<NonZeroUsize>, value: &str) -> Result<(), LexError> {
+    if let Some(max) = max {
+        if value.len() > max.get() {
+            return Err(LexError::StringTooLong(max.get()));
+        }
+    }
+
+    Ok(())
+}
+
 /// _(internals)_ Parse a string literal ended by a specified termination character.
 /// Exported under the `internals` feature only.
 ///
@@ -968,11 +980,8 @@ pub fn parse_string_literal(
             break;
         }
 
-        if let Some(max) = state.max_string_size {
+        ensure_string_len_within_limit(state.max_string_len, &result)
-            if result.len() > max.get() {
+            .map_err(|err| (err, start))?;
-                return Err((LexError::StringTooLong(max.get()), *pos));
-            }
-        }
 
         // Close wrapper
         if termination_char == next_char && escape.is_empty() {
@@ -1107,11 +1116,7 @@ pub fn parse_string_literal(
         }
     }
 
-    if let Some(max) = state.max_string_size {
+    ensure_string_len_within_limit(state.max_string_len, &result).map_err(|err| (err, start))?;
-        if result.len() > max.get() {
-            return Err((LexError::StringTooLong(max.get()), *pos));
-        }
-    }
 
     Ok((result, interpolated, first_char))
 }
@@ -1430,11 +1435,17 @@ fn get_next_token_inner(
             // letter or underscore ...
             #[cfg(not(feature = "unicode-xid-ident"))]
             ('a'..='z' | '_' | 'A'..='Z', ..) => {
-                return Some(get_token_as_identifier(stream, pos, start_pos, c));
+                return Some(
+                    parse_identifier_token(stream, pos, start_pos, c)
+                        .unwrap_or_else(|err| (Token::LexError(err.into()), start_pos)),
+                );
             }
             #[cfg(feature = "unicode-xid-ident")]
             (ch, ..) if unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' => {
-                return Some(get_token_as_identifier(stream, pos, start_pos, c));
+                return Some(
+                    parse_identifier_token(stream, pos, start_pos, c)
+                        .unwrap_or_else(|err| (Token::LexError(err.into()), start_pos)),
+                );
             }
 
             // " - string literal
@@ -1902,12 +1913,12 @@ fn get_next_token_inner(
 }
 
 /// Get the next token, parsing it as an identifier.
-fn get_token_as_identifier(
+fn parse_identifier_token(
     stream: &mut impl InputStream,
     pos: &mut Position,
     start_pos: Position,
     first_char: char,
-) -> (Token, Position) {
+) -> Result<(Token, Position), LexError> {
     let mut identifier = SmartString::new_const();
     identifier.push(first_char);
 
@@ -1922,19 +1933,20 @@ fn get_token_as_identifier(
     }
 
     if let Some(token) = Token::lookup_symbol_from_syntax(&identifier) {
-        return (token, start_pos);
+        return Ok((token, start_pos));
-    } else if Token::is_reserved_keyword(&identifier) {
+    }
-        return (Token::Reserved(Box::new(identifier)), start_pos);
+    if Token::is_reserved_keyword(&identifier) {
+        return Ok((Token::Reserved(Box::new(identifier)), start_pos));
     }
 
     if !is_valid_identifier(&identifier) {
-        return (
+        return Ok((
             Token::LexError(LERR::MalformedIdentifier(identifier.to_string()).into()),
             start_pos,
-        );
+        ));
     }
 
-    (Token::Identifier(identifier.into()), start_pos)
+    Ok((Token::Identifier(identifier.into()), start_pos))
 }
 
 /// Is a keyword allowed as a function?
@@ -2236,10 +2248,7 @@ impl Engine {
             TokenIterator {
                 engine: self,
                 state: TokenizeState {
-                    #[cfg(not(feature = "unchecked"))]
+                    max_string_len: NonZeroUsize::new(self.max_string_size()),
-                    max_string_size: self.limits.max_string_size,
-                    #[cfg(feature = "unchecked")]
-                    max_string_size: None,
                     next_token_cannot_be_unary: false,
                     tokenizer_control: buffer,
                     comment_level: 0,

src/types/parse_error.rs

@@ -19,7 +19,7 @@ pub enum LexError {
     UnexpectedInput(String),
     /// A string literal is not terminated before a new-line or EOF.
     UnterminatedString,
-    /// An identifier is in an invalid format.
+    /// An identifier or string literal is longer than the maximum allowed length.
     StringTooLong(usize),
     /// An string/character/numeric escape sequence is in an invalid format.
     MalformedEscapeSequence(String),
@@ -44,11 +44,7 @@ impl fmt::Display for LexError {
             Self::MalformedChar(s) => write!(f, "Invalid character: '{s}'"),
             Self::MalformedIdentifier(s) => write!(f, "Variable name is not proper: '{s}'"),
             Self::UnterminatedString => f.write_str("Open string is not terminated"),
-            Self::StringTooLong(max) => write!(
+            Self::StringTooLong(max) => write!(f, "String is too long (max {max})"),
-                f,
-                "Length of string literal exceeds the maximum limit ({})",
-                max
-            ),
             Self::ImproperSymbol(s, d) if d.is_empty() => {
                 write!(f, "Invalid symbol encountered: '{s}'")
             }
@@ -262,7 +258,7 @@ impl From<LexError> for ParseErrorType {
     fn from(err: LexError) -> Self {
         match err {
             LexError::StringTooLong(max) => {
-                Self::LiteralTooLarge("Length of string literal".to_string(), max)
+                Self::LiteralTooLarge("Length of string".to_string(), max)
             }
             _ => Self::BadInput(err),
         }

src/types/position.rs

@@ -1,3 +1,4 @@
+//! Script character position type.
 #![cfg(not(feature = "no_position"))]
 
 #[cfg(feature = "no_std")]
@@ -48,6 +49,8 @@ impl Position {
         Self { line, pos: _pos }
     }
     /// Get the line number (1-based), or [`None`] if there is no position.
+    ///
+    /// Always returns [`None`] under `no_position`.
     #[inline]
     #[must_use]
     pub const fn line(self) -> Option<usize> {
@@ -58,6 +61,8 @@ impl Position {
         }
     }
     /// Get the character position (1-based), or [`None`] if at beginning of a line.
+    ///
+    /// Always returns [`None`] under `no_position`.
     #[inline]
     #[must_use]
     pub const fn position(self) -> Option<usize> {
@@ -100,18 +105,24 @@ impl Position {
         }
     }
     /// Is this [`Position`] at the beginning of a line?
+    ///
+    /// Always returns `false` under `no_position`.
     #[inline]
     #[must_use]
     pub const fn is_beginning_of_line(self) -> bool {
         self.pos == 0 && !self.is_none()
     }
     /// Is there no [`Position`]?
+    ///
+    /// Always returns `true` under `no_position`.
     #[inline]
     #[must_use]
     pub const fn is_none(self) -> bool {
         self.line == 0 && self.pos == 0
     }
     /// Returns an fallback [`Position`] if it is [`NONE`][Position::NONE]?
+    ///
+    /// Always returns the fallback under `no_position`.
     #[inline]
     #[must_use]
     pub const fn or_else(self, pos: Self) -> Self {
@@ -219,18 +230,24 @@ impl Span {
         Self { start, end }
     }
     /// Is this [`Span`] non-existent?
+    ///
+    /// Always returns `true` under `no_position`.
     #[inline]
     #[must_use]
     pub const fn is_none(&self) -> bool {
         self.start.is_none() && self.end.is_none()
     }
     /// Get the [`Span`]'s starting [position][Position].
+    ///
+    /// Always returns [`Position::NONE`] under `no_position`.
     #[inline(always)]
     #[must_use]
     pub const fn start(&self) -> Position {
         self.start
     }
     /// Get the [`Span`]'s ending [position][Position].
+    ///
+    /// Always returns [`Position::NONE`] under `no_position`.
     #[inline(always)]
     #[must_use]
     pub const fn end(&self) -> Position {

src/types/position_none.rs

@@ -1,3 +1,4 @@
+//! Placeholder script character position type.
 #![cfg(feature = "no_position")]
 #![allow(unused_variables)]
 
@@ -25,12 +26,16 @@ impl Position {
         Self
     }
     /// Get the line number (1-based), or [`None`] if there is no position.
+    ///
+    /// Always returns [`None`].
     #[inline(always)]
     #[must_use]
     pub const fn line(self) -> Option<usize> {
         None
     }
     /// Get the character position (1-based), or [`None`] if at beginning of a line.
+    ///
+    /// Always returns [`None`].
     #[inline(always)]
     #[must_use]
     pub const fn position(self) -> Option<usize> {
@@ -46,18 +51,24 @@ impl Position {
     #[inline(always)]
     pub(crate) fn new_line(&mut self) {}
     /// Is this [`Position`] at the beginning of a line?
+    ///
+    /// Always returns `false`.
     #[inline(always)]
     #[must_use]
     pub const fn is_beginning_of_line(self) -> bool {
         false
     }
     /// Is there no [`Position`]?
+    ///
+    /// Always returns `true`.
     #[inline(always)]
     #[must_use]
     pub const fn is_none(self) -> bool {
         true
     }
     /// Returns an fallback [`Position`] if it is [`NONE`][Position::NONE]?
+    ///
+    /// Always returns the fallback.
     #[inline(always)]
     #[must_use]
     pub const fn or_else(self, pos: Self) -> Self {
@@ -130,22 +141,28 @@ impl Span {
         Self
     }
     /// Is this [`Span`] non-existent?
+    ///
+    /// Always returns `true`.
     #[inline(always)]
     #[must_use]
     pub const fn is_none(&self) -> bool {
         true
     }
     /// Get the [`Span`]'s starting [position][Position].
+    ///
+    /// Always returns [`Position::NONE`].
     #[inline(always)]
     #[must_use]
     pub const fn start(&self) -> Position {
-        Position
+        Position::NONE
     }
     /// Get the [`Span`]'s ending [position][Position].
+    ///
+    /// Always returns [`Position::NONE`].
     #[inline(always)]
     #[must_use]
     pub const fn end(&self) -> Position {
-        Position
+        Position::NONE
     }
 }