diff --git a/src/deprecated/parse.rs b/src/deprecated/parse.rs
index f7f5cb12f3..6dd784af03 100644
--- a/src/deprecated/parse.rs
+++ b/src/deprecated/parse.rs
@@ -62,7 +62,7 @@ where
         })
 }
 
-fn indentation<I>() -> impl Parser<Input = I, Output = u32>
+fn indentation<I>() -> impl Parser<Input = I, Output = u16>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -136,7 +136,7 @@ where
         .with(value(()))
 }
 
-fn indented_whitespaces<I>(min_indent: u32) -> impl Parser<Input = I, Output = ()>
+fn indented_whitespaces<I>(min_indent: u16) -> impl Parser<Input = I, Output = ()>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -144,7 +144,7 @@ where
     skip_many(skipped_indented_whitespace_char(min_indent))
 }
 
-fn indented_whitespaces1<I>(min_indent: u32) -> impl Parser<Input = I, Output = ()>
+fn indented_whitespaces1<I>(min_indent: u16) -> impl Parser<Input = I, Output = ()>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -152,7 +152,7 @@ where
     skip_many1(skipped_indented_whitespace_char(min_indent))
 }
 
-fn skipped_indented_whitespace_char<I>(min_indent: u32) -> impl Parser<Input = I, Output = ()>
+fn skipped_indented_whitespace_char<I>(min_indent: u16) -> impl Parser<Input = I, Output = ()>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -186,7 +186,7 @@ where
 /// This is separate from expr_body for the sake of function application,
 /// so it can stop parsing when it reaches an operator (since they have
 /// higher precedence.)
-fn function_arg_expr<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+fn function_arg_expr<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -196,10 +196,10 @@ where
 
 parser! {
     #[inline(always)]
-    fn function_arg_expr_[I](min_indent_ref: u32)(I) -> Expr
+    fn function_arg_expr_[I](min_indent_ref: u16)(I) -> Expr
         where [ I: Stream<Item = char, Position = IndentablePosition> ]
     {
-        // TODO figure out why min_indent_ref has the type &mut u32
+        // TODO figure out why min_indent_ref has the type &mut u16
         let min_indent = *min_indent_ref;
 
         // Rules for expressions that can go in function arguments:
@@ -225,7 +225,7 @@ parser! {
     }
 }
 
-fn expr_body<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+fn expr_body<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -236,10 +236,10 @@ where
 // This macro allows recursive parsers
 parser! {
     #[inline(always)]
-    fn expr_body_[I](min_indent_ref: u32)(I) -> Expr
+    fn expr_body_[I](min_indent_ref: u16)(I) -> Expr
         where [ I: Stream<Item = char, Position = IndentablePosition> ]
     {
-        // TODO figure out why min_indent_ref has the type &mut u32
+        // TODO figure out why min_indent_ref has the type &mut u16
         let min_indent = *min_indent_ref;
 
         located(choice((
@@ -272,7 +272,7 @@ parser! {
     }
 }
 
-pub fn if_expr<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn if_expr<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -296,7 +296,7 @@ where
         })
 }
 
-pub fn case_expr<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn case_expr<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -324,7 +324,7 @@ where
         })
 }
 
-pub fn list<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn list<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -348,7 +348,7 @@ where
     })
 }
 
-pub fn apply_with_parens<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn apply_with_parens<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -376,7 +376,7 @@ where
 }
 
 #[inline(always)]
-fn function_arg<I>(min_indent: u32) -> impl Parser<Input = I, Output = Located<Expr>>
+fn function_arg<I>(min_indent: u16) -> impl Parser<Input = I, Output = Located<Expr>>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -405,7 +405,7 @@ where
     )))
 }
 
-pub fn apply_args<I>(min_indent: u32) -> impl Parser<Input = I, Output = Vec<Located<Expr>>>
+pub fn apply_args<I>(min_indent: u16) -> impl Parser<Input = I, Output = Vec<Located<Expr>>>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -493,7 +493,7 @@ where
 }
 
 pub fn nested_assignment<I>(
-    min_indent: u32,
+    min_indent: u16,
 ) -> impl Parser<Input = I, Output = (Located<Pattern>, Located<Expr>)>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
@@ -530,7 +530,7 @@ where
     )
 }
 
-pub fn assignment<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn assignment<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -570,7 +570,7 @@ where
     })
 }
 
-pub fn func_or_var<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn func_or_var<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -594,7 +594,7 @@ where
 }
 
 /// e.g. \x y => expr
-pub fn closure<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn closure<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -616,7 +616,7 @@ where
 
 parser! {
     #[inline(always)]
-    fn pattern[I](min_indent_ref: u32)(I) -> Pattern
+    fn pattern[I](min_indent_ref: u16)(I) -> Pattern
         where [ I: Stream<Item = char, Position = IndentablePosition> ]
     {
         let min_indent = *min_indent_ref;
@@ -631,7 +631,7 @@ parser! {
     }
 }
 
-pub fn apply_variant<I>(min_indent: u32) -> impl Parser<Input = I, Output = Expr>
+pub fn apply_variant<I>(min_indent: u16) -> impl Parser<Input = I, Output = Expr>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
@@ -643,7 +643,7 @@ where
         })
 }
 
-pub fn match_variant<I>(min_indent: u32) -> impl Parser<Input = I, Output = Pattern>
+pub fn match_variant<I>(min_indent: u16) -> impl Parser<Input = I, Output = Pattern>
 where
     I: Stream<Item = char, Position = IndentablePosition>,
     I::Error: ParseError<I::Item, I::Range, I::Position>,
diff --git a/src/deprecated/parse_state.rs b/src/deprecated/parse_state.rs
index 66afe99487..970b9b36fb 100644
--- a/src/deprecated/parse_state.rs
+++ b/src/deprecated/parse_state.rs
@@ -18,10 +18,10 @@ pub struct IndentablePosition {
     /// Current line of the input
     pub line: u32,
     /// Current column of the input
-    pub column: u32,
+    pub column: u16,
 
     /// Current indentation level, in columns (so no indent is col 1 - this saves an arithmetic operation.)
-    pub indent_col: u32,
+    pub indent_col: u16,
 
     // true at the beginning of each line, then false after encountering the first nonspace char.
     pub is_indenting: bool,
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 0ec8dc8ebf..c9816d6d70 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -7,9 +7,6 @@ use parse::ast::Expr;
 use parse::parser::Parser;
 use parse::string_literal::string_literal;
 
-pub fn expr<'a, 'p>() -> impl Parser<'a, 'p, Expr<'a>>
-where
-    'p: 'a,
-{
+pub fn expr<'a>() -> impl Parser<'a, Expr<'a>> {
     string_literal()
 }
diff --git a/src/parse/string_literal.rs b/src/parse/string_literal.rs
index 7a7203aa5b..833a7dc2ed 100644
--- a/src/parse/string_literal.rs
+++ b/src/parse/string_literal.rs
@@ -99,7 +99,7 @@ fn escaped_char_problem<'a, 'p>(
     buf_len: usize,
 ) {
     let start_line = state.line;
-    let start_col = state.column + buf_len as u32;
+    let start_col = state.column + buf_len as u16;
     let end_line = start_line;
     // escapes should all be 2 chars long
     let end_col = state.column + 1;
@@ -126,11 +126,11 @@ fn escaped_unicode_problem<'a, 'p>(
 ) {
     let start_line = state.line;
     // +1 due to the `"` which precedes buf.
-    let start_col = state.column + buf_len as u32 + 1;
+    let start_col = state.column + buf_len as u16 + 1;
     let end_line = start_line;
     // +3 due to the `\u{` and another + 1 due to the `}`
     // -1 to prevent overshooting because end col is inclusive.
-    let end_col = start_col + 3 + hex_str_len as u32 + 1 - 1;
+    let end_col = start_col + 3 + hex_str_len as u16 + 1 - 1;
 
     let region = Region {
         start_line,
@@ -209,7 +209,7 @@ where
     if chars.next() != Some('{') {
         let start_line = state.line;
         // +1 due to the `"` which precedes buf
-        let start_col = state.column + 1 + buf.len() as u32;
+        let start_col = state.column + 1 + buf.len() as u16;
         let end_line = start_line;
 
         // All we parsed was `\u`, so end on the column after `\`'s column.
@@ -251,13 +251,13 @@ where
                             let start_line = state.line;
                             // +1 due to the `"` which precedes buf
                             // +3 due to the `\u{` which precedes the hex digits
-                            let start_col = state.column + 1 + buf.len() as u32 + 3;
+                            let start_col = state.column + 1 + buf.len() as u16 + 3;
                             let end_line = start_line;
 
                             // We want to underline only the number. That's the error!
                             // -1 because we want to end on the last digit, not
                             // overshoot it.
-                            let end_col = start_col + hex_str.len() as u32 - 1;
+                            let end_col = start_col + hex_str.len() as u16 - 1;
 
                             let region = Region {
                                 start_line,
@@ -355,11 +355,11 @@ where
             // parsing logic can consume the quote and do its job as normal.
             let start_line = state.line;
             // +1 due to the `"` which precedes buf.
-            let start_col = state.column + buf.len() as u32 + 1;
+            let start_col = state.column + buf.len() as u16 + 1;
             let end_line = start_line;
             // +3 due to the `\u{`
             // -1 to prevent overshooting because end col is inclusive.
-            let end_col = start_col + 3 + hex_str.len() as u32 - 1;
+            let end_col = start_col + 3 + hex_str.len() as u16 - 1;
 
             let region = Region {
                 start_line,
diff --git a/src/region.rs b/src/region.rs
index a647f57a9f..add2a11049 100644
--- a/src/region.rs
+++ b/src/region.rs
@@ -5,11 +5,16 @@ pub type Loc<T> = Located<T>;
 
 #[derive(Clone, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Region {
+    pub start_col: u16,
+    pub end_col: u16,
     pub start_line: u32,
-    pub start_col: u32,
-
     pub end_line: u32,
-    pub end_col: u32,
+}
+
+#[test]
+fn region_size() {
+    // Region is used all over the place. Avoid increasing its size!
+    assert_eq!(std::mem::size_of::<Region>(), 8);
 }
 
 impl fmt::Debug for Region {