Merge pull request #543 from Carltoffel/fix-string-concat

Fix string concat

Author: milancurcic

src/stdlib_string_type.fypp

@@ -1082,7 +1082,7 @@ contains
         type(string_type), intent(in) :: rhs
         type(string_type) :: string
 
-        string%raw = maybe(rhs) // maybe(lhs)
+        string%raw = maybe(lhs) // maybe(rhs)
 
     end function concat_string_string
 

src/tests/string/test_string_operator.f90

@@ -99,11 +99,15 @@ subroutine test_ne
     end subroutine test_ne
 
     subroutine test_concat
-        type(string_type) :: string
-
-        string = "Hello, "
-        string = string // "World!"
-        call check(len(string) == 13)
+        type(string_type) :: a, b
+
+        a = "a"
+        b = "b"
+        call check( "a" //  b  == "ab" )
+        call check( a  // "b" == "ab" )
+        call check( a  //  b  == "ab" )
+        call check( a  //  ""  == "a" )
+        call check( ""  //  b  == "b" )
     end subroutine test_concat
 
 end module test_string_operator