Refactor to support multiple parse errors (#8765)

# Description

This is a pretty heavy refactor of the parser to support multiple parser
errors. It has a few issues we should address before landing:

- [x] In some cases, error quality has gotten worse `1 / "bob"` for
example
- [x] if/else isn't currently parsing correctly
- probably others

# User-Facing Changes

This may have error quality degradation as we adjust to the new error
reporting mechanism.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-utils/standard_library/tests.nu` to run the
tests for the standard library

> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-cli/src/commands.rs

@@ -34,9 +34,9 @@ pub fn evaluate_commands(
 
         let mut working_set = StateWorkingSet::new(engine_state);
 
-        let (output, err) = parse(&mut working_set, None, commands.item.as_bytes(), false, &[]);
-        if let Some(err) = err {
-            report_error(&working_set, &err);
+        let output = parse(&mut working_set, None, commands.item.as_bytes(), false, &[]);
+        if let Some(err) = working_set.parse_errors.first() {
+            report_error(&working_set, err);
 
             std::process::exit(1);
         }

crates/nu-cli/src/completions/completer.rs

@@ -120,7 +120,7 @@ impl NuCompleter {
         let pos = offset + pos;
         let config = self.engine_state.get_config();
 
-        let (output, _err) = parse(&mut working_set, Some("completer"), &new_line, false, &[]);
+        let output = parse(&mut working_set, Some("completer"), &new_line, false, &[]);
 
         for pipeline in output.pipelines.into_iter() {
             for pipeline_element in pipeline.elements {

crates/nu-cli/src/config_files.rs

@@ -1,14 +1,12 @@
 use crate::util::eval_source;
 use nu_command::util::report_error;
 #[cfg(feature = "plugin")]
-use nu_parser::ParseError;
-#[cfg(feature = "plugin")]
 use nu_path::canonicalize_with;
 use nu_protocol::engine::{EngineState, Stack, StateWorkingSet};
-#[cfg(feature = "plugin")]
-use nu_protocol::Spanned;
 use nu_protocol::{HistoryFileFormat, PipelineData};
 #[cfg(feature = "plugin")]
+use nu_protocol::{ParseError, Spanned};
+#[cfg(feature = "plugin")]
 use nu_utils::utils::perf;
 use std::path::PathBuf;
 

crates/nu-cli/src/reedline_config.rs

@@ -97,7 +97,7 @@ pub(crate) fn add_menus(
         {
             let (block, _) = {
                 let mut working_set = StateWorkingSet::new(&engine_state);
-                let (output, _) = parse(
+                let output = parse(
                     &mut working_set,
                     Some(name), // format!("entry #{}", entry_num)
                     definition.as_bytes(),

crates/nu-cli/src/repl.rs

@@ -789,7 +789,7 @@ pub fn eval_string_with_input(
 ) -> Result<Value, ShellError> {
     let (block, delta) = {
         let mut working_set = StateWorkingSet::new(engine_state);
-        let (output, _) = parse(&mut working_set, None, source.as_bytes(), false, &[]);
+        let output = parse(&mut working_set, None, source.as_bytes(), false, &[]);
 
         (output, working_set.render())
     };

crates/nu-cli/src/syntax_highlight.rs

@@ -18,10 +18,7 @@ impl Highlighter for NuHighlighter {
         trace!("highlighting: {}", line);
 
         let mut working_set = StateWorkingSet::new(&self.engine_state);
-        let block = {
-            let (block, _) = parse(&mut working_set, None, line.as_bytes(), false, &[]);
-            block
-        };
+        let block = parse(&mut working_set, None, line.as_bytes(), false, &[]);
         let (shapes, global_span_offset) = {
             let shapes = flatten_block(&working_set, &block);
             (shapes, self.engine_state.next_span_start())

crates/nu-cli/src/util.rs

@@ -113,7 +113,8 @@ fn gather_env_vars(
                 span,
             }) = parts.get(0)
             {
-                let bytes = engine_state.get_span_contents(span);
+                let mut working_set = StateWorkingSet::new(engine_state);
+                let bytes = working_set.get_span_contents(*span);
 
                 if bytes.len() < 2 {
                     report_capture_error(
@@ -125,9 +126,12 @@ fn gather_env_vars(
                     continue;
                 }
 
-                let (bytes, parse_error) = unescape_unquote_string(bytes, *span);
+                let (bytes, err) = unescape_unquote_string(bytes, *span);
+                if let Some(err) = err {
+                    working_set.error(err);
+                }
 
-                if parse_error.is_some() {
+                if working_set.parse_errors.first().is_some() {
                     report_capture_error(
                         engine_state,
                         &String::from_utf8_lossy(contents),
@@ -153,7 +157,8 @@ fn gather_env_vars(
                 span,
             }) = parts.get(2)
             {
-                let bytes = engine_state.get_span_contents(span);
+                let mut working_set = StateWorkingSet::new(engine_state);
+                let bytes = working_set.get_span_contents(*span);
 
                 if bytes.len() < 2 {
                     report_capture_error(
@@ -165,9 +170,12 @@ fn gather_env_vars(
                     continue;
                 }
 
-                let (bytes, parse_error) = unescape_unquote_string(bytes, *span);
+                let (bytes, err) = unescape_unquote_string(bytes, *span);
+                if let Some(err) = err {
+                    working_set.error(err);
+                }
 
-                if parse_error.is_some() {
+                if working_set.parse_errors.first().is_some() {
                     report_capture_error(
                         engine_state,
                         &String::from_utf8_lossy(contents),
@@ -209,16 +217,16 @@ pub fn eval_source(
 
     let (block, delta) = {
         let mut working_set = StateWorkingSet::new(engine_state);
-        let (output, err) = parse(
+        let output = parse(
             &mut working_set,
             Some(fname), // format!("entry #{}", entry_num)
             source,
             false,
             &[],
         );
-        if let Some(err) = err {
+        if let Some(err) = working_set.parse_errors.first() {
             set_last_exit_code(stack, 1);
-            report_error(&working_set, &err);
+            report_error(&working_set, err);
             return false;
         }
 

crates/nu-cli/src/validation.rs

@@ -1,5 +1,8 @@
-use nu_parser::{parse, ParseError};
-use nu_protocol::engine::{EngineState, StateWorkingSet};
+use nu_parser::parse;
+use nu_protocol::{
+    engine::{EngineState, StateWorkingSet},
+    ParseError,
+};
 use reedline::{ValidationResult, Validator};
 use std::sync::Arc;
 
@@ -10,9 +13,12 @@ pub struct NuValidator {
 impl Validator for NuValidator {
     fn validate(&self, line: &str) -> ValidationResult {
         let mut working_set = StateWorkingSet::new(&self.engine_state);
-        let (_, err) = parse(&mut working_set, None, line.as_bytes(), false, &[]);
+        parse(&mut working_set, None, line.as_bytes(), false, &[]);
 
-        if matches!(err, Some(ParseError::UnexpectedEof(..))) {
+        if matches!(
+            working_set.parse_errors.first(),
+            Some(ParseError::UnexpectedEof(..))
+        ) {
             ValidationResult::Incomplete
         } else {
             ValidationResult::Complete