complex abs return type test; fixes #1836

stan-dev · Apr 13, 2020 · 8ccdd28 · 8ccdd28
1 parent 4b3eb6f
commit 8ccdd28
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/test/unit/math/mix/fun/abs_test.cpp b/test/unit/math/mix/fun/abs_test.cpp
@@ -2,8 +2,9 @@
 #include <cmath>
 #include <complex>
 #include <vector>
+#include <type_traits>
 
-TEST(mixScalFun, abs) {
+TEST(mixFun, abs) {
   auto f = [](const auto& x) {
     using std::abs;
     return abs(x);
@@ -29,3 +30,12 @@ TEST(mixScalFun, abs) {
     }
   }
 }
+TEST(mixFun, absReturnType) {
+  // validate return types not overpromoted to complex by assignability
+  std::complex<stan::math::var> a = 3;
+  stan::math::var b = abs(a);
+
+  std::complex<stan::math::fvar<double>> c = 3;
+  stan::math::fvar<double> d = abs(c);
+  SUCCEED();
+}