diff --git a/lib/rewriter.js b/lib/rewriter.js
index cb571dcb..6999fc88 100644
--- a/lib/rewriter.js
+++ b/lib/rewriter.js
@@ -1,5 +1,5 @@
 (function() {
-  var BALANCED_PAIRS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_BLOCK, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, INVERSES, LINEBREAKS, SINGLE_CLOSERS, SINGLE_LINERS, _i, _len, _ref, include, left, rite;
+  var BALANCED_PAIRS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_BLOCK, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, IMPLICIT_UNSPACED_CALL, INVERSES, LINEBREAKS, SINGLE_CLOSERS, SINGLE_LINERS, _i, _len, _ref, include, left, rite;
   include = require('./helpers').include;
   exports.Rewriter = (function() {
     function Rewriter() {
@@ -197,7 +197,7 @@
       if (prev && !prev.spaced && tag === '?') {
         token.call = true;
       }
-      if (!(callObject || ((prev != null) ? prev.spaced : undefined) && (prev.call || include(IMPLICIT_FUNC, prev[0])) && include(IMPLICIT_CALL, tag))) {
+      if (!(callObject || ((prev != null) ? prev.spaced : undefined) && (prev.call || include(IMPLICIT_FUNC, prev[0])) && (include(IMPLICIT_CALL, tag) || include(IMPLICIT_UNSPACED_CALL, tag) && !token.spaced))) {
         return 1;
       }
       tokens.splice(i, 0, ['CALL_START', '(', token[2]]);
@@ -368,7 +368,8 @@
   }
   EXPRESSION_CLOSE = ['CATCH', 'WHEN', 'ELSE', 'FINALLY'].concat(EXPRESSION_END);
   IMPLICIT_FUNC = ['IDENTIFIER', 'SUPER', ')', 'CALL_END', ']', 'INDEX_END', '@', 'THIS'];
-  IMPLICIT_CALL = ['IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'CLASS', 'IF', 'UNLESS', 'TRY', 'SWITCH', 'THIS', 'BOOL', 'UNARY', '@', '->', '=>', '[', '(', '{'];
+  IMPLICIT_CALL = ['IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'CLASS', 'IF', 'UNLESS', 'TRY', 'SWITCH', 'THIS', 'BOOL', 'UNARY', '@', '->', '=>', '[', '(', '{', '--', '++'];
+  IMPLICIT_UNSPACED_CALL = ['+', '-'];
   IMPLICIT_BLOCK = ['->', '=>', '{', '[', ','];
   IMPLICIT_END = ['POST_IF', 'POST_UNLESS', 'FOR', 'WHILE', 'UNTIL', 'LOOP', 'TERMINATOR', 'INDENT'];
   SINGLE_LINERS = ['ELSE', '->', '=>', 'TRY', 'FINALLY', 'THEN'];
diff --git a/src/rewriter.coffee b/src/rewriter.coffee
index 627ac515..5ea02984 100644
--- a/src/rewriter.coffee
+++ b/src/rewriter.coffee
@@ -168,7 +168,7 @@ class exports.Rewriter
       token.call = yes if prev and not prev.spaced and tag is '?'
       return 1 unless callObject or
         prev?.spaced and (prev.call or include(IMPLICIT_FUNC, prev[0])) and
-        include(IMPLICIT_CALL, tag)
+        (include(IMPLICIT_CALL, tag) or include(IMPLICIT_UNSPACED_CALL, tag) and not token.spaced)
       tokens.splice i, 0, ['CALL_START', '(', token[2]]
       @detectEnd i + (if callObject then 2 else 1), (token, i) ->
         return yes if not seenSingle and token.fromThen
@@ -329,9 +329,11 @@ IMPLICIT_FUNC    = ['IDENTIFIER', 'SUPER', ')', 'CALL_END', ']', 'INDEX_END', '@
 IMPLICIT_CALL    = [
   'IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'CLASS'
   'IF', 'UNLESS', 'TRY', 'SWITCH', 'THIS', 'BOOL', 'UNARY',
-  '@', '->', '=>', '[', '(', '{'
+  '@', '->', '=>', '[', '(', '{', '--', '++'
 ]
 
+IMPLICIT_UNSPACED_CALL = ['+', '-']
+
 # Tokens indicating that the implicit call must enclose a block of expressions.
 IMPLICIT_BLOCK   = ['->', '=>', '{', '[', ',']
 
diff --git a/test/test_functions.coffee b/test/test_functions.coffee
index 7bd3dd17..c39e6c0f 100644
--- a/test/test_functions.coffee
+++ b/test/test_functions.coffee
@@ -317,19 +317,30 @@ func = ->
 eq func(), 101
 
 
-#619: `new` shouldn't add extra parens
+# `new` shouldn't add extra parens
 ok new Date().constructor is Date
 
 
-#717: `new` works against bare function
+# `new` works against bare function
 eq Date, new ->
   eq this, new => this
   Date
 
 
-#751: Implicit objects with number arguments.
+# Implicit objects with number arguments.
 func = (x, y) -> y
 obj =
   prop: func "a", 1
 
 ok obj.prop is 1
+
+
+# Non-spaced unary and binary operators should cause a function call.
+func = (val) -> val + 1
+ok (func +5) is 6
+ok (func -5) is -4
+
+
+# Prefix unary assignment operators are allowed in parenless calls.
+val = 5
+ok (func --val) is 5