diff --git a/src/func.rs b/src/func.rs
index 2cdd026c2..33cc6e838 100644
--- a/src/func.rs
+++ b/src/func.rs
@@ -132,7 +132,7 @@ macro_rules! function {
                 let func = $code;
 
                 for arg in header.args.into_iter() {
-                    feedback.errors.push(err!(arg.span(); "unexpected argument"));
+                    feedback.errors.push(err!(arg.span; "unexpected argument"));
                 }
 
                 $crate::Pass::new(func, feedback)
diff --git a/src/syntax/func/mod.rs b/src/syntax/func/mod.rs
index 54d34531c..fd516208f 100644
--- a/src/syntax/func/mod.rs
+++ b/src/syntax/func/mod.rs
@@ -42,17 +42,22 @@ impl FuncArgs {
     }
 
     /// Add an argument.
-    pub fn add(&mut self, arg: FuncArg) {
-        match arg {
-            FuncArg::Pos(item) => self.pos.add(item),
-            FuncArg::Key(pair) => self.key.add(pair),
+    pub fn add(&mut self, arg: Spanned<FuncArg>) {
+        match arg.v {
+            FuncArg::Pos(item) => self.pos.add(Spanned::new(item, arg.span)),
+            FuncArg::Key(pair) => self.key.add(Spanned::new(pair, arg.span)),
         }
     }
 
     /// Iterate over all arguments.
-    pub fn into_iter(self) -> impl Iterator<Item=FuncArg> {
-        self.pos.items.into_iter().map(|item| FuncArg::Pos(item))
-            .chain(self.key.pairs.into_iter().map(|pair| FuncArg::Key(pair)))
+    pub fn into_iter(self) -> impl Iterator<Item=Spanned<FuncArg>> {
+        let pos = self.pos.items.into_iter()
+            .map(|spanned| spanned.map(|item| FuncArg::Pos(item)));
+
+        let key = self.key.pairs.into_iter()
+        .map(|spanned| spanned.map(|pair| FuncArg::Key(pair)));
+
+        pos.chain(key)
     }
 }
 
@@ -60,7 +65,7 @@ impl FromIterator<Spanned<FuncArg>> for FuncArgs {
     fn from_iter<I: IntoIterator<Item=Spanned<FuncArg>>>(iter: I) -> Self {
         let mut args = FuncArgs::new();
         for item in iter.into_iter() {
-            args.add(item.v);
+            args.add(item);
         }
         args
     }
@@ -70,22 +75,9 @@ impl FromIterator<Spanned<FuncArg>> for FuncArgs {
 #[derive(Debug, Clone, PartialEq)]
 pub enum FuncArg {
     /// A positional argument.
-    Pos(Spanned<Expr>),
+    Pos(Expr),
     /// A keyword argument.
-    Key(Spanned<Pair>),
-}
-
-impl FuncArg {
-    /// The full span of this argument.
-    ///
-    /// In case of a positional argument this is just the span of the expression
-    /// and in case of a keyword argument the combined span of key and value.
-    pub fn span(&self) -> Span {
-        match self {
-            FuncArg::Pos(item) => item.span,
-            FuncArg::Key(item) => item.span,
-        }
-    }
+    Key(Pair),
 }
 
 /// Extra methods on [`Options`](Option) used for argument parsing.
diff --git a/src/syntax/parsing.rs b/src/syntax/parsing.rs
index 07dfec7cb..9636df210 100644
--- a/src/syntax/parsing.rs
+++ b/src/syntax/parsing.rs
@@ -190,10 +190,8 @@ impl<'s> FuncParser<'s> {
             if let Some(ident) = p.parse_ident() {
                 // This could still be a named tuple
                 if let Some(Token::LeftParen) = p.peekv() {
-                    let n_tuple = p.parse_named_tuple(ident)
-                        .map(|t| Expr::NamedTuple(t));
-                    let span = n_tuple.span;
-                    return Ok(Spanned::new(FuncArg::Pos(n_tuple), span));
+                    let tuple = p.parse_named_tuple(ident);
+                    return Ok(tuple.map(|t| FuncArg::Pos(Expr::NamedTuple(t))));
                 }
 
                 p.skip_whitespace();
@@ -210,22 +208,18 @@ impl<'s> FuncParser<'s> {
 
                     // Add a keyword argument.
                     let span = Span::merge(ident.span, value.span);
-                    Ok(Spanned::new(
-                        FuncArg::Key(Spanned::new(Pair { key: ident, value }, span)),
-                        span,
-                    ))
+                    let pair = Pair { key: ident, value };
+                    Ok(Spanned::new(FuncArg::Key(pair), span))
                 } else {
                     // Add a positional argument because there was no equals
                     // sign after the identifier that could have been a key.
-                    let ident = ident.map(|id| Expr::Ident(id));
-                    let span = ident.span;
-                    Ok(Spanned::new(FuncArg::Pos(ident), span))
+                    Ok(ident.map(|id| FuncArg::Pos(Expr::Ident(id))))
                 }
             } else {
                 // Add a positional argument because we haven't got an
                 // identifier that could be an argument key.
-                p.parse_expr().map(|expr| Spanned { span: expr.span, v: FuncArg::Pos(expr) })
-                    .ok_or(("argument", None))
+                let value = p.parse_expr().ok_or(("argument", None))?;
+                Ok(value.map(|expr| FuncArg::Pos(expr)))
             }
         }).v
     }