From 17a7b3e03ffdf460f0ce31f6a834e3c903436bf4 Mon Sep 17 00:00:00 2001
From: David Widmann <dev+github@devmotion.de>
Date: Mon, 23 Jul 2018 01:23:35 +0200
Subject: [PATCH] Only consider functions with at least two arguments

---
 src/MuladdMacro.jl | 10 +++++-----
 test/runtests.jl   |  8 ++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/MuladdMacro.jl b/src/MuladdMacro.jl
index a526dd8..908c158 100644
--- a/src/MuladdMacro.jl
+++ b/src/MuladdMacro.jl
@@ -85,10 +85,10 @@ end
 """
     iscall(ex, op)
 
-Determine whether `ex` is a call of operation `op`.
+Determine whether `ex` is a call of operation `op` with at least two arguments.
 """
 iscall(ex::Expr, op) =
-    ex.head == :call && !isempty(ex.args) && ex.args[1] == op
+    ex.head == :call && length(ex.args) > 2 && ex.args[1] == op
 iscall(ex, op) = false
 
 """
@@ -104,11 +104,11 @@ isdotcall(ex) = false
 """
     isdotcall(ex, op)
 
-Determine whether `ex` is a dot call of operation `op`.
+Determine whether `ex` is a dot call of operation `op` with at least two arguments.
 """
 isdotcall(ex::Expr, op) =
-    (ex.head == :. && length(ex.args) == 2 && ex.args[1] == op && Meta.isexpr(ex.args[2], :tuple)) ||
-    (ex.head == :call && !isempty(ex.args) && ex.args[1] == Symbol('.', op))
+    (ex.head == :. && length(ex.args) == 2 && ex.args[1] == op && Meta.isexpr(ex.args[2], :tuple) && length(ex.args[2].args) > 1) ||
+    (ex.head == :call && length(ex.args) > 2 && ex.args[1] == Symbol('.', op))
 isdotcall(ex, op) = false
 
 """
diff --git a/test/runtests.jl b/test/runtests.jl
index d1a4544..d7551b8 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -40,12 +40,16 @@ end
             :($(Base.muladd)(e, f, $(Base.muladd)(c, d, a*b)))
         @test @macroexpand(@muladd a*(b*c+d)+e) ==
             :($(Base.muladd)(a, $(Base.muladd)(b, c, d), e))
+
+        @test @macroexpand(@muladd +a) == :(+a)
     end
 
     @testset "Subtraction" begin
         @test @macroexpand(@muladd a*b-c*d) == :($(Base.muladd)(-c, d, a*b))
         @test @macroexpand(@muladd a*(b*c-d)-e) ==
             :($(Base.muladd)(a, $(Base.muladd)(b, c, -d), -e))
+
+        @test @macroexpand(@muladd -a) == :(-a)
     end
 end
 
@@ -64,6 +68,8 @@ end
         @test @macroexpand(@muladd f.(a)*b+c) == :($(Base.muladd)(f.(a), b, c))
         @test @macroexpand(@muladd a*f.(b)+c) == :($(Base.muladd)(a, f.(b), c))
         @test @macroexpand(@muladd a*b+f.(c)) == :($(Base.muladd)(a, b, f.(c)))
+
+        @test @macroexpand(@muladd .+a) == :(.+a)
     end
 
     @testset "Subtraction" begin
@@ -76,6 +82,8 @@ end
         @test @macroexpand(@muladd @. a-b*c) == :($(Base.muladd).((-).(b), c, a))
         @test @macroexpand(@muladd a-b.*c) == :(a-b.*c)
         @test @macroexpand(@muladd a.-b*c) == :(a.-b*c)
+
+        @test @macroexpand(@muladd .-a) == :(.-a)
     end
 end