I guess main can return Results now.

src/bin/accounting.rs

@@ -4,7 +4,7 @@ use std::env;
 use std::fs;
 use std::str::FromStr;
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut numbers = Vec::new();
 
     for argument in env::args().skip(1) {
@@ -118,10 +118,4 @@ fn next_target(low_index: usize, high_index: usize, avoid: &[usize]) -> Option<u
     }
 
     None
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/baggage.rs

@@ -186,7 +186,7 @@ fn parse_rule_item(input0: &str) -> nom::IResult<&str, Rule> {
     Ok((input6, Rule { count, bag }))
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut rules = RuleSet::empty();
 
     for argument in env::args().skip(1) {
@@ -211,10 +211,4 @@ fn real_main() -> Result<(), TopLevelError> {
     );
 
     Ok(())
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/boarding_pass.rs

@@ -119,7 +119,7 @@ fn example_boarding_passes() {
     );
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut seats = BTreeSet::new();
     let mut highest_id = 0;
 
@@ -147,10 +147,4 @@ fn real_main() -> Result<(), TopLevelError> {
     }
 
     Err(TopLevelError::NoSolutionFound)
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/customs_form.rs

@@ -3,7 +3,7 @@ use std::collections::BTreeSet;
 use std::env;
 use std::fs;
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut customs_forms_any = Vec::new();
     let mut customs_forms_all = Vec::new();
 
@@ -73,10 +73,4 @@ fn every_seat() -> BTreeSet<char> {
     }
 
     result
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/machine.rs

@@ -154,7 +154,7 @@ impl Iterator for VariantGenerator {
     }
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let filename = env::args().skip(1).next().expect("No file argument given.");
     let contents = fs::read_to_string(filename)?;
     let machine = Machine::from_str(&contents)?;
@@ -177,10 +177,4 @@ fn real_main() -> Result<(), TopLevelError> {
     }
 
     Ok(())
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/passport.rs

@@ -137,7 +137,7 @@ fn valid_year_range(field: &Option<String>, start: u64, end: u64) -> bool {
     true
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut passports = Vec::new();
 
     for argument in env::args().skip(1) {
@@ -169,10 +169,4 @@ fn real_main() -> Result<(), TopLevelError> {
     );
 
     Ok(())
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/password_check.rs

@@ -64,7 +64,7 @@ impl PasswordData {
     }
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut good_items_interpretation1 = 0u64;
     let mut good_items_interpretation2 = 0u64;
 
@@ -96,10 +96,4 @@ fn real_main() -> Result<(), TopLevelError> {
     );
 
     Ok(())
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}

src/bin/tobaggan.rs

@@ -49,7 +49,7 @@ fn trail_for_slope(map: &Map<Square>, run: usize, fall: usize) -> Encounters {
     encounters
 }
 
-fn real_main() -> Result<(), TopLevelError> {
+fn main() -> Result<(), TopLevelError> {
     let mut maybe_map = None;
 
     for argument in env::args().skip(1) {
@@ -90,10 +90,4 @@ fn real_main() -> Result<(), TopLevelError> {
     println!("The product of the trees encountered is {}", product);
 
     Ok(())
-}
-
-fn main() {
-    if let Err(e) = real_main() {
-        eprintln!("ERROR: {}", e);
-    }
-}
+}