add Into<String> arg for error constructors

schala-lang/language/src/parsing.rs

@@ -17,8 +17,8 @@ pub struct ParseError {
 }
 
 impl ParseError {
-  fn new_with_token<T>(msg: &str, token: Token) -> ParseResult<T>{
-    Err(ParseError { msg: msg.to_string(), token })
+  fn new_with_token<T, M>(msg: M, token: Token) -> ParseResult<T> where M: Into<String> {
+    Err(ParseError { msg: msg.into(), token })
   }
 }
 
@@ -112,7 +112,7 @@ macro_rules! expect {
         $expected_kind if $cond => $self.token_handler.next(),
         actual_kind => {
           let msg = format!("Expected {}, got {:?}", print_token_pattern!($expected_kind), actual_kind);
-          return ParseError::new_with_token(&msg, tok);
+          return ParseError::new_with_token(msg, tok);
         }
       }
     }
@@ -864,7 +864,7 @@ impl Parser {
           self.token_handler.next();
           Pattern::Ignored
         },
-        other => return ParseError::new_with_token(&format!("{:?} is not a valid Pattern", other), tok)
+        other => return ParseError::new_with_token(format!("{:?} is not a valid Pattern", other), tok)
       }
     })
   }
@@ -982,7 +982,7 @@ impl Parser {
     let tok = self.token_handler.next();
     match tok.get_kind() {
       Identifier(s) => Ok(s),
-      p => ParseError::new_with_token(&format!("Expected an identifier, got {:?}", p), tok),
+      p => ParseError::new_with_token(format!("Expected an identifier, got {:?}", p), tok),
     }
   }
 
@@ -1005,7 +1005,7 @@ impl Parser {
         self.token_handler.next();
         Ok(Expression(StringLiteral(s.clone()), None))
       }
-      e => ParseError::new_with_token(&format!("Expected a literal expression, got {:?}", e), tok),
+      e => ParseError::new_with_token(format!("Expected a literal expression, got {:?}", e), tok),
     }
   }
 
@@ -1047,13 +1047,13 @@ impl Parser {
       digits.push_str(&self.digits()?);
       match digits.parse::<f64>() {
         Ok(f) => Ok(Expression(FloatLiteral(f), None)),
-        Err(e) => ParseError::new_with_token(&format!("Float failed to parse with error: {}", e), tok),
+        Err(e) => ParseError::new_with_token(format!("Float failed to parse with error: {}", e), tok),
 
       }
     } else {
       match digits.parse::<u64>() {
         Ok(d) => Ok(Expression(NatLiteral(d), None)),
-        Err(e) => ParseError::new_with_token(&format!("Integer failed to parse with error: {}", e), tok),
+        Err(e) => ParseError::new_with_token(format!("Integer failed to parse with error: {}", e), tok),
       }
     }
   }

schala-lang/language/src/typechecking.rs

@@ -22,8 +22,8 @@ type InferResult<T> = Result<T, TypeError>;
 pub struct TypeError { pub msg: String }
 
 impl TypeError {
-  fn new<A>(msg: &str) -> InferResult<A> { //TODO make these kinds of error-producing functions CoW-ready
-    Err(TypeError { msg: msg.to_string() })
+  fn new<A, T>(msg: T) -> InferResult<A> where T: Into<String> { //TODO make these kinds of error-producing functions CoW-ready
+    Err(TypeError { msg: msg.into() })
   }
 }
 
@@ -267,7 +267,7 @@ impl<'a> TypeContext<'a> {
         let _ = self.unify(*t1.clone(), tx)?;
         *t2.clone()
       },
-      _ => return TypeError::new(&format!("Not a function"))
+      _ => return TypeError::new(format!("Not a function"))
     })
   }
 
@@ -275,7 +275,7 @@ impl<'a> TypeContext<'a> {
     use self::Discriminator::*; use self::IfExpressionBody::*;
     match (discriminator, body) {
       (Simple(expr), SimpleConditional(then_clause, else_clause)) => self.handle_simple_if(expr, then_clause, else_clause),
-      _ => TypeError::new(&format!("Complex conditionals not supported"))
+      _ => TypeError::new(format!("Complex conditionals not supported"))
     }
   }
 
@@ -307,7 +307,7 @@ impl<'a> TypeContext<'a> {
   fn handle_value(&mut self, val: &Rc<String>) -> InferResult<Type> {
     match self.variable_map.lookup(val) {
       Some(ty) => Ok(ty.clone()),
-      None => TypeError::new(&format!("Couldn't find variable: {}", val))
+      None => TypeError::new(format!("Couldn't find variable: {}", val))
     }
   }
 
@@ -315,7 +315,7 @@ impl<'a> TypeContext<'a> {
     use self::Type::*; use self::TypeConst::*;
     Ok(match (t1, t2) {
       (Const(ref c1), Const(ref c2)) if c1 == c2 => Const(c1.clone()), //choice of c1 is arbitrary I *think*
-      (a, b) => return TypeError::new(&format!("{:?} and {:?} do not unify", a, b)),
+      (a, b) => return TypeError::new(format!("{:?} and {:?} do not unify", a, b)),
     })
   }
 }