Trying to check if a string contains at least one invalid character

containstest/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "containstest"
+version = "0.1.0"

containstest/Cargo.toml

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+[package]
+name = "containstest"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

containstest/README.md

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+# ContaintsTest
+
+Finding a way to check if any of multiple characters exist in string.

containstest/src/main.rs

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+const INVALID: &'static str =  " ()[]/\"\\";
+
+fn invalid(check: &str) -> bool {
+    check.chars().any(|char| INVALID.contains(char))
+}
+
+fn main() {
+    let str = "thisisfine";
+    println!("{} - {}", str, invalid(str));
+
+    let str = "this is not fine";
+    println!("{} - {}", str, invalid(str));
+}