For your first error, you can do some foot-shooting with a statically typed language too.
I remember a bug I made using C#, where I wanted to delete a collection of directories recursively. I got mixed up into the various inner loops and ended up iterating over the characters like you. But C# allows implicit conversions of char to string so the compiler was OK with it, and since those where network drive directories (starting with "\\server\"), the first iteration started deleting recursively the directory "\", which in windows means the root directory of the active drive (c:\)... And SSDs are fast at deleting stuff.
I remember a bug I made using C#, where I wanted to delete a collection of directories recursively. I got mixed up into the various inner loops and ended up iterating over the characters like you. But C# allows implicit conversions of char to string so the compiler was OK with it, and since those where network drive directories (starting with "\\server\"), the first iteration started deleting recursively the directory "\", which in windows means the root directory of the active drive (c:\)... And SSDs are fast at deleting stuff.