Add keep_shadowed_builtins feature to roc_parse

compiler/parse/Cargo.toml

@@ -5,6 +5,11 @@ authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 edition = "2018"
 
+[features]
+# If enabled, parser accepts `Dict.#hashTestOnly` etc.
+# For development puporpse.
+keep_shadowed_builtins = []
+
 [dependencies]
 roc_collections = { path = "../collections" }
 roc_region = { path = "../region" }

compiler/parse/src/ident.rs

@@ -220,6 +220,10 @@ pub enum BadIdent {
     BadPrivateTag(Row, Col),
 }
 
+fn chomp_lowercase_part_keep_shadowed_builtins(buffer: &[u8]) -> Result<&str, Progress> {
+    chomp_part(|c: char| c.is_lowercase() || c == '#', buffer)
+}
+
 fn chomp_lowercase_part(buffer: &[u8]) -> Result<&str, Progress> {
     chomp_part(|c: char| c.is_lowercase(), buffer)
 }
@@ -499,19 +503,24 @@ fn chomp_access_chain<'a>(buffer: &'a [u8], parts: &mut Vec<'a, &'a str>) -> Res
 
     while let Some(b'.') = buffer.get(chomped) {
         match &buffer.get(chomped + 1..) {
-            Some(slice) => match chomp_lowercase_part(slice) {
+            Some(slice) => {
-                Ok(name) => {
+                let res = match cfg!(feature = "keep_shadowed_builtins") {
-                    let value = unsafe {
+                    true => chomp_lowercase_part_keep_shadowed_builtins(slice),
-                        std::str::from_utf8_unchecked(
+                    false => chomp_lowercase_part(slice),
-                            &buffer[chomped + 1..chomped + 1 + name.len()],
+                };
-                        )
+                match res {
-                    };
+                    Ok(name) => {
-                    parts.push(value);
+                        let value = unsafe {
-
+                            std::str::from_utf8_unchecked(
-                    chomped += name.len() + 1;
+                                &buffer[chomped + 1..chomped + 1 + name.len()],
+                            )
+                        };
+                        parts.push(value);
+                        chomped += name.len() + 1;
+                    }
+                    Err(_) => return Err(chomped as u16 + 1),
                 }
-                Err(_) => return Err(chomped as u16 + 1),
+            }
-            },
             None => return Err(chomped as u16 + 1),
         }
     }