Parser - Removed handling of 'return' special cases

* This has been implemented in the resolver so it's pretty pointless
    to do it twice

src/parser.rs

@@ -492,24 +492,16 @@ impl Parser {
     /// return_statement := "return" expression? ";"
     /// ```
     fn parse_return_statement(&mut self, ret_token: &Token) -> SloxResult<StmtNode> {
-        if self.can_use_return() {
-            let value = if self.check(&TokenType::Semicolon) {
-                None
-            } else {
-                Some(self.parse_expression()?)
-            };
-            self.consume(&TokenType::Semicolon, "';' expected after return statement")?;
-            Ok(StmtNode::Return {
-                token: ret_token.clone(),
-                value,
-            })
+        let value = if self.check(&TokenType::Semicolon) {
+            None
         } else {
-            Err(SloxError::with_token(
-                ErrorKind::Parse,
-                ret_token,
-                "'return' found outside of function".to_owned(),
-            ))
-        }
+            Some(self.parse_expression()?)
+        };
+        self.consume(&TokenType::Semicolon, "';' expected after return statement")?;
+        Ok(StmtNode::Return {
+            token: ret_token.clone(),
+            value,
+        })
     }
 
     /// Parse the following rule:
@@ -861,19 +853,6 @@ impl Parser {
         false
     }
 
-    /// Check whether the `return` keyword can be used. This is true whenever
-    /// the first `LoopParsingState::None` found in the loop parsing state is
-    /// not the one at position 0.
-    fn can_use_return(&self) -> bool {
-        let mut pos = self.loop_state.len() - 1;
-        loop {
-            if self.loop_state[pos] == LoopParsingState::None {
-                return pos != 0;
-            }
-            pos -= 1;
-        }
-    }
-
     /// Generate an error at the current token.
     fn error<O>(&self, message: &str) -> SloxResult<O> {
         self.error_mv(message.to_owned())