Minor cleanup

src/grammar.coffee

@@ -225,11 +225,10 @@ grammar =
   ]
 
   # The **Code** node is the function literal. It's defined by an indented block
-  # of **Block** preceded by a function arrow, with an optional parameter
-  # list.
+  # of **Block** preceded by a function arrow, with an optional parameter list.
   Code: [
     o 'PARAM_START ParamList PARAM_END FuncGlyph Block', -> new Code $2, $5, $4
-    o 'FuncGlyph Block',                        -> new Code [], $2, $1
+    o 'FuncGlyph Block',                                 -> new Code [], $2, $1
   ]
 
   # CoffeeScript has two different symbols for functions. `->` is for ordinary

src/nodes.coffee

@@ -1661,8 +1661,8 @@ exports.Code = class Code extends Base
       params[i] = p.compileToFragments o
       o.scope.parameter fragmentsToText params[i]
     uniqs = []
-    @eachParamName (name, node) ->
-      node.error "multiple parameters named #{name}" if name in uniqs
+    @eachParamName (name, node) =>
+      node.error "multiple parameters named '#{name}'" if name in uniqs
       uniqs.push name
     @body.makeReturn() unless wasEmpty or @noReturn
     code = 'function'
@@ -1729,7 +1729,7 @@ exports.Param = class Param extends Base
   # The `iterator` function will be called as `iterator(name, node)` where
   # `name` is the name of the parameter and `node` is the AST node corresponding
   # to that name.
-  eachName: (iterator, name = @name)->
+  eachName: (iterator, name = @name) ->
     atParam = (obj) -> iterator "@#{obj.properties[0].name.value}", obj
     # * simple literals `foo`
     return iterator name.value, name if name instanceof Literal

test/error_messages.coffee

@@ -642,14 +642,14 @@ test "duplicate function arguments", ->
   assertErrorFormat '''
     (foo, bar, foo) ->
   ''', '''
-    [stdin]:1:12: error: multiple parameters named foo
+    [stdin]:1:12: error: multiple parameters named 'foo'
     (foo, bar, foo) ->
                ^^^
   '''
   assertErrorFormat '''
     (@foo, bar, @foo) ->
   ''', '''
-    [stdin]:1:13: error: multiple parameters named @foo
+    [stdin]:1:13: error: multiple parameters named '@foo'
     (@foo, bar, @foo) ->
                 ^^^^
   '''