diff --git a/src/bisection.jl b/src/bisection.jl
index 940eaeb7b..c00ed19c2 100644
--- a/src/bisection.jl
+++ b/src/bisection.jl
@@ -27,7 +27,7 @@ function perform_step(solver::BracketingImmutableSolver, alg::Bisection, cache)
   if cache.state == 0
     fzero = zero(fl)
     fl * fr > fzero && error("Bracket became non-containing in between iterations. This could mean that "
-    + "input function crosses the x axis multiple times. Bisection is not the right method to solve this.")
+    * "input function crosses the x axis multiple times. Bisection is not the right method to solve this.")
 
     mid = (left + right) / 2
     
diff --git a/src/falsi.jl b/src/falsi.jl
index e93291de8..2700bdbe9 100644
--- a/src/falsi.jl
+++ b/src/falsi.jl
@@ -14,7 +14,7 @@ function perform_step(solver, alg::Falsi, cache)
 
   fzero = zero(fl)
   fl * fr > fzero && error("Bracket became non-containing in between iterations. This could mean that "
-  + "input function crosses the x axis multiple times. Bisection is not the right method to solve this.")
+  * "input function crosses the x axis multiple times. Bisection is not the right method to solve this.")
 
   mid = (fr * left - fl * right) / (fr - fl)