diff --git a/std/internal/math/errorfunction.d b/std/internal/math/errorfunction.d
index 9be6ac6c3..6c57a364d 100644
--- a/std/internal/math/errorfunction.d
+++ b/std/internal/math/errorfunction.d
@@ -25,6 +25,11 @@
 module std.internal.math.errorfunction;
 import std.math;
 
+pure:
+nothrow:
+@safe:
+@nogc:
+
 private {
 immutable real EXP_2  = 0.13533528323661269189L; /* exp(-2) */
 enum real SQRT2PI = 2.50662827463100050242E0L; // sqrt(2pi)
diff --git a/std/internal/math/gammafunction.d b/std/internal/math/gammafunction.d
index d54e53922..28aafce93 100644
--- a/std/internal/math/gammafunction.d
+++ b/std/internal/math/gammafunction.d
@@ -22,6 +22,11 @@ module std.internal.math.gammafunction;
 import std.internal.math.errorfunction;
 import std.math;
 
+pure:
+nothrow:
+@safe:
+@nogc:
+
 private {
 
 enum real SQRT2PI = 2.50662827463100050242E0L; // sqrt(2pi)
@@ -490,7 +495,7 @@ unittest {
     assert(logGamma(-real.min_normal*real.epsilon) == real.infinity);
 
     // x, correct loggamma(x), correct d/dx loggamma(x).
-    static real[] testpoints = [
+    immutable static real[] testpoints = [
     8.0L,                    8.525146484375L      + 1.48766904143001655310E-5,   2.01564147795560999654E0L,
     8.99993896484375e-1L,    6.6375732421875e-2L  + 5.11505711292524166220E-6L, -7.54938684259372234258E-1,
     7.31597900390625e-1L,    2.2369384765625e-1   + 5.21506341809849792422E-6L, -1.13355566660398608343E0L,
diff --git a/std/mathspecial.d b/std/mathspecial.d
index b67e3ff62..d8ba22ac6 100644
--- a/std/mathspecial.d
+++ b/std/mathspecial.d
@@ -62,7 +62,12 @@ private import std.internal.math.errorfunction;
 /* ***********************************************
  *            GAMMA AND RELATED FUNCTIONS        *
  * ***********************************************/
-//pure nothrow:
+
+pure:
+nothrow:
+@safe:
+@nogc:
+
 /** The Gamma function, $(GAMMA)(x)
  *
  *  $(GAMMA)(x) is a generalisation of the factorial function
diff --git a/unittest.d b/unittest.d
index f2858027c..9d64a8f64 100644
--- a/unittest.d
+++ b/unittest.d
@@ -102,7 +102,7 @@ int main(char[][] args)
     assert(x[2] == 45);
 
     cast(void)std.math.sin(3.0);
-    std.mathspecial.gamma(6.2);
+    cast(void)std.mathspecial.gamma(6.2);
 
     std.demangle.demangle("hello");