Clean up some stale comments

src/builtins/source.rs

@@ -83,7 +83,7 @@ pub fn source(parser: &Parser, streams: &mut IoStreams, args: &mut [&wstr]) -> O
         Some(func_filename.clone()),
     );
 
-    // Construct argv from our null-terminated list.
+    // Construct argv for the sourced file from our remaining args.
     // This is slightly subtle. If this is a bare `source` with no args then `argv + optind` already
     // points to the end of argv. Otherwise we want to skip the file name to get to the args if any.
     let remaining_args = &args[optind + if argc == optind { 0 } else { 1 }..];
@@ -105,7 +105,5 @@ pub fn source(parser: &Parser, streams: &mut IoStreams, args: &mut [&wstr]) -> O
         retval = parser.get_last_status();
     }
 
-    // Do not close fd after calling reader_read. reader_read automatically closes it before calling
-    // eval.
     Some(retval)
 }

src/common.rs

@@ -1942,8 +1942,8 @@ pub trait Named {
     fn name(&self) -> &'static wstr;
 }
 
-/// Return a pointer to the first entry with the given name, assuming the entries are sorted by
-/// name. Return nullptr if not found.
+/// Return a reference to the first entry with the given name, assuming the entries are sorted by
+/// name. Return None if not found.
 pub fn get_by_sorted_name<T: Named>(name: &wstr, vals: &'static [T]) -> Option<&'static T> {
     match vals.binary_search_by_key(&name, |val| val.name()) {
         Ok(index) => Some(&vals[index]),

src/parser.rs

@@ -860,7 +860,7 @@ impl Parser {
         }
     }
 
-    /// Pushes a new block. Returns a pointer to the block, stored in the parser.
+    /// Pushes a new block. Returns an id (index) of the block, which is stored in the parser.
     pub fn push_block(&self, mut block: Block) -> BlockId {
         block.src_lineno = self.get_lineno();
         block.src_filename = self.current_filename();

src/screen.rs

@@ -1363,8 +1363,7 @@ impl LayoutCache {
         }
     }
 
-    /// Finds the layout for a prompt, promoting it to the front. Returns nullptr if not found.
-    /// Note this points into our cache; do not modify the cache while the pointer lives.
+    /// Finds the layout for a prompt, promoting it to the front. Returns whether this was found.
     /// Exposed for testing.
     pub fn find_prompt_layout(
         &mut self,