Simplify code.

src/ast/ast.rs

@@ -189,11 +189,7 @@ impl AST {
             .as_mut()
             .map(|m| m.set_id(source.clone()));
 
-        if source.is_empty() {
+        self.source = (!source.is_empty()).then(|| source);
-            self.source = None;
-        } else {
-            self.source = Some(source);
-        }
 
         self
     }
@@ -240,12 +236,7 @@ impl AST {
     #[inline(always)]
     pub(crate) fn set_doc(&mut self, doc: impl Into<crate::SmartString>) {
         let doc = doc.into();
-
+        self.doc = (!doc.is_empty()).then(|| doc.into());
-        if doc.is_empty() {
-            self.doc = None;
-        } else {
-            self.doc = Some(doc.into());
-        }
     }
     /// Get the statements.
     #[cfg(not(feature = "internals"))]

src/ast/expr.rs

@@ -248,11 +248,7 @@ impl FnCallExpr {
     #[inline]
     #[must_use]
     pub fn constant_args(&self) -> bool {
-        if self.args.is_empty() {
+        self.args.is_empty() || self.args.iter().all(Expr::is_constant)
-            true
-        } else {
-            self.args.iter().all(Expr::is_constant)
-        }
     }
 }
 

src/eval/cache.rs

@@ -63,8 +63,8 @@ impl Caches {
     #[inline]
     #[must_use]
     pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
+        // Push a new function resolution cache if the stack is empty
         if self.0.is_empty() {
-            // Push a new function resolution cache if the stack is empty
             self.push_fn_resolution_cache();
         }
         self.0.last_mut().unwrap()

src/eval/chaining.rs

@@ -504,9 +504,7 @@ impl Engine {
                     global, caches, scope, this_ptr, expr, rhs, idx_values,
                 )?;
 
-                if !_arg_values.is_empty() {
+                idx_values.extend(_arg_values);
-                    idx_values.extend(_arg_values);
-                }
             }
 
             #[cfg(not(feature = "no_object"))]

src/eval/stmt.rs

@@ -304,12 +304,14 @@ impl Engine {
                     .as_bool()
                     .map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
 
-                if guard_val && !if_block.is_empty() {
+                match guard_val {
-                    self.eval_stmt_block(global, caches, scope, this_ptr, if_block, true)
+                    true if !if_block.is_empty() => {
-                } else if !guard_val && !else_block.is_empty() {
+                        self.eval_stmt_block(global, caches, scope, this_ptr, if_block, true)
-                    self.eval_stmt_block(global, caches, scope, this_ptr, else_block, true)
+                    }
-                } else {
+                    false if !else_block.is_empty() => {
-                    Ok(Dynamic::UNIT)
+                        self.eval_stmt_block(global, caches, scope, this_ptr, else_block, true)
+                    }
+                    _ => Ok(Dynamic::UNIT),
                 }
             }
 
@@ -512,12 +514,10 @@ impl Engine {
                 auto_restore! { scope => rewind; let orig_scope_len = scope.len(); }
 
                 // Add the loop variables
-                let counter_index = if counter.is_empty() {
+                let counter_index = (!counter.is_empty()).then(|| {
-                    usize::MAX
-                } else {
                     scope.push(counter.name.clone(), 0 as INT);
                     scope.len() - 1
-                };
+                });
 
                 scope.push(var_name.name.clone(), ());
                 let index = scope.len() - 1;
@@ -526,7 +526,7 @@ impl Engine {
 
                 for (x, iter_value) in iter_func(iter_obj).enumerate() {
                     // Increment counter
-                    if counter_index < usize::MAX {
+                    if let Some(counter_index) = counter_index {
                         // As the variable increments from 0, this should always work
                         // since any overflow will first be caught below.
                         let index_value = x as INT;

src/func/call.rs

@@ -816,7 +816,8 @@ impl Engine {
                 if call_args.is_empty() {
                     let typ = self.map_type_name(target.type_name());
                     return Err(self.make_type_mismatch_err::<FnPtr>(typ, fn_call_pos));
-                } else if !call_args[0].is_fnptr() {
+                }
+                if !call_args[0].is_fnptr() {
                     let typ = self.map_type_name(call_args[0].type_name());
                     return Err(self.make_type_mismatch_err::<FnPtr>(typ, first_arg_pos));
                 }
@@ -1257,9 +1258,7 @@ impl Engine {
         }
 
         // Call with blank scope
-        if total_args == 0 && curry.is_empty() {
+        if total_args > 0 || !curry.is_empty() {
-            // No arguments
-        } else {
             // If the first argument is a variable, and there is no curried arguments,
             // convert to method-call style in order to leverage potential &mut first argument and
             // avoid cloning the value
@@ -1330,9 +1329,7 @@ impl Engine {
         let args = &mut FnArgsVec::with_capacity(args_expr.len());
         let mut first_arg_value = None;
 
-        if args_expr.is_empty() {
+        if !args_expr.is_empty() {
-            // No arguments
-        } else {
             // See if the first argument is a variable (not namespace-qualified).
             // If so, convert to method-call style in order to leverage potential &mut first argument
             // and avoid cloning the value

src/module/mod.rs

@@ -361,13 +361,7 @@ impl Module {
     #[inline(always)]
     pub fn set_id(&mut self, id: impl Into<ImmutableString>) -> &mut Self {
         let id = id.into();
-
+        self.id = (!id.is_empty()).then(|| id);
-        if id.is_empty() {
-            self.id = None;
-        } else {
-            self.id = Some(id);
-        }
-
         self
     }
 
@@ -2330,21 +2324,9 @@ impl Module {
             self.flags
                 .set(ModuleFlags::INDEXED_GLOBAL_FUNCTIONS, has_global_functions);
 
-            self.all_variables = if variables.is_empty() {
+            self.all_variables = (!variables.is_empty()).then(|| variables.into());
-                None
+            self.all_functions = (!functions.is_empty()).then(|| functions.into());
-            } else {
+            self.all_type_iterators = (!type_iterators.is_empty()).then(|| type_iterators.into());
-                Some(variables.into())
-            };
-            self.all_functions = if functions.is_empty() {
-                None
-            } else {
-                Some(functions.into())
-            };
-            self.all_type_iterators = if type_iterators.is_empty() {
-                None
-            } else {
-                Some(type_iterators.into())
-            };
 
             self.flags |= ModuleFlags::INDEXED;
         }

src/module/resolvers/file.rs

@@ -239,14 +239,7 @@ impl FileModuleResolver {
         if !self.cache_enabled {
             return false;
         }
-
+        locked_read(&self.cache).contains_key(path.as_ref())
-        let cache = locked_read(&self.cache);
-
-        if cache.is_empty() {
-            false
-        } else {
-            cache.contains_key(path.as_ref())
-        }
     }
     /// Empty the internal cache.
     #[inline]

src/module/resolvers/stat.rs

@@ -73,11 +73,7 @@ impl StaticModuleResolver {
     #[inline(always)]
     #[must_use]
     pub fn contains_path(&self, path: &str) -> bool {
-        if self.0.is_empty() {
+        self.0.contains_key(path)
-            false
-        } else {
-            self.0.contains_key(path)
-        }
     }
     /// Get an iterator of all the [modules][Module].
     #[inline]
@@ -123,9 +119,7 @@ impl StaticModuleResolver {
     /// Existing modules of the same path name are overwritten.
     #[inline]
     pub fn merge(&mut self, other: Self) -> &mut Self {
-        if !other.is_empty() {
+        self.0.extend(other.0.into_iter());
-            self.0.extend(other.0.into_iter());
-        }
         self
     }
 }

src/parser.rs

@@ -25,7 +25,6 @@ use bitflags::bitflags;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
-    collections::BTreeMap,
     convert::TryFrom,
     fmt,
     hash::{Hash, Hasher},
@@ -979,7 +978,7 @@ impl Engine {
         settings.pos = eat_token(input, Token::MapStart);
 
         let mut map = StaticVec::<(Ident, Expr)>::new();
-        let mut template = BTreeMap::<Identifier, crate::Dynamic>::new();
+        let mut template = std::collections::BTreeMap::<Identifier, crate::Dynamic>::new();
 
         loop {
             const MISSING_RBRACE: &str = "to end this object map literal";