added if3 based on: Using if in a let Statement

info.toml

@@ -167,6 +167,13 @@ For that first compiler error, it's important in Rust that each conditional
 block returns the same type! To get the tests passing, you will need a couple
 conditions checking different input values."""
 
+[[exercises]]
+name = "if3"
+path = "exercises/if/if3.rs"
+mode = "test"
+hint = """
+In Rust, every arm of an `if` expression has to return the same type of value. Make sure the type is consistent across all arms."""
+
 # QUIZ 1
 
 [[exercises]]