diff --git a/json/lex_main.mbt b/json/lex_main.mbt
index 9e290a65c..327ff3c90 100644
--- a/json/lex_main.mbt
+++ b/json/lex_main.mbt
@@ -30,67 +30,67 @@ fn lex_value(
   for ; ; {
     match read_char(ctx) {
       Some('\t' | ' ' | '\n' | '\r') => continue
-      Some('{') => return Ok(LBrace)
-      Some('[') => return Ok(LBracket)
+      Some('{') => break Ok(LBrace)
+      Some('[') => break Ok(LBracket)
       Some(']') =>
         if allow_rbracket {
-          return Ok(RBracket)
+          break Ok(RBracket)
         } else {
-          return Err(invalid_char(ctx, shift=-1))
+          break Err(invalid_char(ctx, shift=-1))
         }
       Some('n') => {
         lex_assert_char(ctx, 'u')?
         lex_assert_char(ctx, 'l')?
         lex_assert_char(ctx, 'l')?
-        return Ok(Null)
+        break Ok(Null)
       }
       Some('t') => {
         lex_assert_char(ctx, 'r')?
         lex_assert_char(ctx, 'u')?
         lex_assert_char(ctx, 'e')?
-        return Ok(True)
+        break Ok(True)
       }
       Some('f') => {
         lex_assert_char(ctx, 'a')?
         lex_assert_char(ctx, 'l')?
         lex_assert_char(ctx, 's')?
         lex_assert_char(ctx, 'e')?
-        return Ok(False)
+        break Ok(False)
       }
       Some('-') =>
         match read_char(ctx) {
           Some('0') => {
             let n = lex_zero(ctx, start=ctx.offset - 2)!!
-            return Ok(Number(n))
+            break Ok(Number(n))
           }
           Some(c2) => {
             if c2 >= '1' && c2 <= '9' {
               let n = lex_decimal_integer(ctx, start=ctx.offset - 2)!!
-              return Ok(Number(n))
+              break Ok(Number(n))
             }
-            return Err(invalid_char(ctx, shift=-1))
+            break Err(invalid_char(ctx, shift=-1))
           }
-          None => return Err(InvalidEof)
+          None => break Err(InvalidEof)
         }
       Some('0') => {
         let n = lex_zero(ctx, start=ctx.offset - 1)!!
-        return Ok(Number(n))
+        break Ok(Number(n))
       }
       Some('1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9') => {
         let n = lex_decimal_integer(ctx, start=ctx.offset - 1)!!
-        return Ok(Number(n))
+        break Ok(Number(n))
       }
       Some('"') => {
         let s = lex_string(ctx)?
-        return Ok(String(s))
+        break Ok(String(s))
       }
       Some(c) => {
         if c > '\x7f' && non_ascii_whitespace.contains(c) {
           continue
         }
-        return Err(invalid_char(ctx, shift=-1))
+        break Err(invalid_char(ctx, shift=-1))
       }
-      None => return Err(InvalidEof)
+      None => break Err(InvalidEof)
     }
   }
 }
diff --git a/json/lex_number.mbt b/json/lex_number.mbt
index 732e02863..d357b5c6a 100644
--- a/json/lex_number.mbt
+++ b/json/lex_number.mbt
@@ -15,16 +15,16 @@
 fn lex_decimal_integer(ctx : ParseContext, ~start : Int) -> Double!ParseError {
   for ; ; {
     match read_char(ctx) {
-      Some('.') => return lex_decimal_point(ctx, ~start)!
-      Some('e' | 'E') => return lex_decimal_exponent(ctx, ~start)!
+      Some('.') => break lex_decimal_point(ctx, ~start)!
+      Some('e' | 'E') => break lex_decimal_exponent(ctx, ~start)!
       Some(c) => {
         if c >= '0' && c <= '9' {
           continue
         }
         ctx.offset -= 1
-        return lex_number_end(ctx, start, ctx.offset)!
+        break lex_number_end(ctx, start, ctx.offset)!
       }
-      None => return lex_number_end(ctx, start, ctx.offset)!
+      None => break lex_number_end(ctx, start, ctx.offset)!
     }
   }
 }
@@ -33,7 +33,7 @@ fn lex_decimal_point(ctx : ParseContext, ~start : Int) -> Double!ParseError {
   match read_char(ctx) {
     Some(c) =>
       if c >= '0' && c <= '9' {
-        return lex_decimal_fraction(ctx, ~start)!
+        lex_decimal_fraction(ctx, ~start)!
       } else {
         raise invalid_char(ctx, shift=-1)
       }
@@ -46,22 +46,22 @@ fn lex_decimal_point(ctx : ParseContext, ~start : Int) -> Double!ParseError {
 fn lex_decimal_fraction(ctx : ParseContext, ~start : Int) -> Double!ParseError {
   for ; ; {
     match read_char(ctx) {
-      Some('e' | 'E') => return lex_decimal_exponent(ctx, ~start)!
+      Some('e' | 'E') => break lex_decimal_exponent(ctx, ~start)!
       Some(c) => {
         if c >= '0' && c <= '9' {
           continue
         }
         ctx.offset -= 1
-        return lex_number_end(ctx, start, ctx.offset)!
+        break lex_number_end(ctx, start, ctx.offset)!
       }
-      None => return lex_number_end(ctx, start, ctx.offset)!
+      None => break lex_number_end(ctx, start, ctx.offset)!
     }
   }
 }
 
 fn lex_decimal_exponent(ctx : ParseContext, ~start : Int) -> Double!ParseError {
   match read_char(ctx) {
-    Some('+') | Some('-') => return lex_decimal_exponent_sign(ctx, ~start)!
+    Some('+') | Some('-') => lex_decimal_exponent_sign(ctx, ~start)!
     Some(c) => {
       if c >= '0' && c <= '9' {
         return lex_decimal_exponent_integer(ctx, ~start)!
@@ -104,26 +104,26 @@ fn lex_decimal_exponent_integer(
           continue
         }
         ctx.offset -= 1
-        return lex_number_end(ctx, start, ctx.offset)!
+        break lex_number_end(ctx, start, ctx.offset)!
       }
-      None => return lex_number_end(ctx, start, ctx.offset)!
+      None => break lex_number_end(ctx, start, ctx.offset)!
     }
   }
 }
 
 fn lex_zero(ctx : ParseContext, ~start : Int) -> Double!ParseError {
   match read_char(ctx) {
-    Some('.') => return lex_decimal_point(ctx, ~start)!
-    Some('e' | 'E') => return lex_decimal_exponent(ctx, ~start)!
+    Some('.') => lex_decimal_point(ctx, ~start)!
+    Some('e' | 'E') => lex_decimal_exponent(ctx, ~start)!
     Some(c) => {
       if c >= '0' && c <= '9' {
         ctx.offset -= 1
         raise invalid_char(ctx)
       }
       ctx.offset -= 1
-      return lex_number_end(ctx, start, ctx.offset)!
+      lex_number_end(ctx, start, ctx.offset)!
     }
-    None => return lex_number_end(ctx, start, ctx.offset)!
+    None => lex_number_end(ctx, start, ctx.offset)!
   }
 }