better indentation errors (use original location for error)

compiler/parse/src/blankspace.rs

@@ -444,6 +444,9 @@ where
         let mut state = state;
         let mut any_newlines = false;
 
+        let start_row = original_state.line;
+        let start_col = original_state.column;
+
         let start_bytes_len = state.bytes.len();
 
         while !state.bytes.is_empty() {
@@ -491,7 +494,13 @@ where
                                     let progress =
                                         Progress::from_lengths(start_bytes_len, state.bytes.len());
                                     state = state
-                                        .check_indent_e(arena, min_indent, indent_problem)
+                                        .check_indent_e(
+                                            arena,
+                                            min_indent,
+                                            indent_problem,
+                                            start_row,
+                                            start_col,
+                                        )
                                         .map_err(|(fail, _)| {
                                             (progress, fail, original_state.clone())
                                         })?
@@ -523,7 +532,13 @@ where
                                         );
                                         if any_newlines {
                                             state = state
-                                                .check_indent_e(arena, min_indent, indent_problem)
+                                                .check_indent_e(
+                                                    arena,
+                                                    min_indent,
+                                                    indent_problem,
+                                                    start_row,
+                                                    start_col,
+                                                )
                                                 .map_err(|(fail, _)| {
                                                     (progress, fail, original_state.clone())
                                                 })?;
@@ -692,7 +707,13 @@ where
                                 progress,
                                 space_slice,
                                 state
-                                    .check_indent_e(arena, min_indent, indent_problem)
+                                    .check_indent_e(
+                                        arena,
+                                        min_indent,
+                                        indent_problem,
+                                        start_row,
+                                        start_col,
+                                    )
                                     .map_err(|(fail, _)| (progress, fail, original_state))?,
                             ));
                         }
@@ -720,7 +741,7 @@ where
             let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
             if any_newlines {
                 state = state
-                    .check_indent_e(arena, min_indent, indent_problem)
+                    .check_indent_e(arena, min_indent, indent_problem, start_row, start_col)
                     .map_err(|(fail, _)| (progress, fail, original_state))?;
             }
 

compiler/parse/src/parser.rs

@@ -72,12 +72,14 @@ impl<'a> State<'a> {
         _arena: &'a Bump,
         min_indent: u16,
         to_error: TE,
+        row: Row,
+        col: Col,
     ) -> Result<Self, (E, Self)>
     where
         TE: Fn(Row, Col) -> E,
     {
         if self.indent_col < min_indent {
-            Err((to_error(self.line, self.column), self))
+            Err((to_error(row, col), self))
         } else {
             Ok(self)
         }
@@ -378,6 +380,7 @@ pub enum Type<'a> {
     TStart(Row, Col),
     TEnd(Row, Col),
     TSpace(BadInputError, Row, Col),
+    TFunctionArgument(Row, Col),
     ///
     TIndentStart(Row, Col),
     TIndentEnd(Row, Col),
@@ -1496,6 +1499,31 @@ where
     }
 }
 
+pub fn check_indent<'a, TE, E>(min_indent: u16, to_problem: TE) -> impl Parser<'a, (), E>
+where
+    TE: Fn(Row, Col) -> E,
+    E: 'a,
+{
+    move |_arena, state: State<'a>| {
+        dbg!(state.indent_col, min_indent);
+        if state.indent_col < min_indent {
+            Err((NoProgress, to_problem(state.line, state.column), state))
+        } else {
+            Ok((NoProgress, (), state))
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! word1_check_indent {
+    ($word:expr, $word_problem:expr, $min_indent:expr, $indent_problem:expr) => {
+        and!(
+            word1($word, $word_problem),
+            crate::parser::check_indent($min_indent, $indent_problem)
+        )
+    };
+}
+
 #[allow(dead_code)]
 fn in_context<'a, AddContext, P1, P2, Start, A, X, Y>(
     add_context: AddContext,

compiler/parse/src/type_annotation.rs

@@ -1,15 +1,13 @@
 use crate::ast::{AssignedField, CommentOrNewline, Tag, TypeAnnotation};
-use crate::blankspace::{
+use crate::blankspace::{space0_around_e, space0_before_e, space0_e};
-    space0, space0_around, space0_around_e, space0_before, space0_before_e, space0_e,
-};
 use crate::expr::{global_tag, private_tag};
 use crate::ident::join_module_parts;
 use crate::keyword;
 use crate::parser::{
-    allocated, ascii_char, ascii_string, backtrackable, not_e, optional, peek_utf8_char_e,
+    allocated, backtrackable, not_e, optional, peek_utf8_char_e, specialize, specialize_ref, word1,
-    specialize, specialize_ref, word1, word2, BadInputError, Col, Either, ParseResult, Parser,
+    word2, BadInputError, Either, ParseResult, Parser,
     Progress::{self, *},
-    Row, State, SyntaxError, TApply, TInParens, TRecord, TTagUnion, TVariable, Type,
+    State, SyntaxError, TApply, TInParens, TRecord, TTagUnion, TVariable, Type,
 };
 use bumpalo::collections::string::String;
 use bumpalo::collections::vec::Vec;
@@ -54,20 +52,6 @@ fn tag_union_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, TT
     }
 }
 
-fn check_indent<'a, TE, E>(min_indent: u16, to_problem: TE) -> impl Parser<'a, (), E>
-where
-    TE: Fn(Row, Col) -> E,
-    E: 'a,
-{
-    move |_arena, state: State<'a>| {
-        if state.indent_col < min_indent {
-            Err((NoProgress, to_problem(state.line, state.column), state))
-        } else {
-            Ok((NoProgress, (), state))
-        }
-    }
-}
-
 #[allow(clippy::type_complexity)]
 fn term<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
     specialize(|x, _, _| SyntaxError::Type(x), term_help(min_indent))
@@ -247,7 +231,7 @@ fn record_type_field<'a>(
         debug_assert_eq!(progress, MadeProgress);
 
         let (_, spaces, state) =
-            space0_e(min_indent, TRecord::Space, TRecord::IndentEnd).parse(arena, state)?;
+            debug!(space0_e(min_indent, TRecord::Space, TRecord::IndentEnd)).parse(arena, state)?;
 
         // Having a value is optional; both `{ email }` and `{ email: blah }` work.
         // (This is true in both literals and types.)
@@ -312,9 +296,11 @@ fn record_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, TReco
 
     move |arena, state| {
         let (_, (fields, final_comments), state) = collection_trailing_sep_e!(
+            // word1_check_indent!(b'{', TRecord::Open, min_indent, TRecord::IndentOpen),
             word1(b'{', TRecord::Open),
             loc!(record_type_field(min_indent)),
             word1(b',', TRecord::End),
+            // word1_check_indent!(b'}', TRecord::End, min_indent, TRecord::IndentEnd),
             word1(b'}', TRecord::End),
             min_indent,
             TRecord::Open,
@@ -377,13 +363,20 @@ fn expression<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>
         .parse(arena, state)?;
 
         let (p2, rest, state) = zero_or_more!(skip_first!(
-            word1(b',', Type::TStart),
+            word1(b',', Type::TFunctionArgument),
-            space0_around_e(
+            one_of![
-                term_help(min_indent),
+                space0_around_e(
-                min_indent,
+                    term_help(min_indent),
-                Type::TSpace,
+                    min_indent,
-                Type::TIndentStart
+                    Type::TSpace,
-            )
+                    Type::TIndentStart
+                ),
+                |_, state: State<'a>| Err((
+                    NoProgress,
+                    Type::TFunctionArgument(state.line, state.column),
+                    state
+                ))
+            ]
         ))
         .parse(arena, state)?;
 

compiler/reporting/src/error/parse.rs

@@ -102,6 +102,24 @@ fn to_syntax_report<'a>(
 
             report(doc)
         }
+        SyntaxError::Eof(region) => {
+            let doc = alloc.stack(vec![alloc.reflow("End of Field"), alloc.region(*region)]);
+
+            Report {
+                filename,
+                doc,
+                title: "PARSE PROBLEM".to_string(),
+            }
+        }
+        SyntaxError::OutdentedTooFar => {
+            let doc = alloc.stack(vec![alloc.reflow("OutdentedTooFar")]);
+
+            Report {
+                filename,
+                doc,
+                title: "PARSE PROBLEM".to_string(),
+            }
+        }
         Type(typ) => to_type_report(alloc, filename, &typ, 0, 0),
         _ => todo!("unhandled parse error: {:?}", parse_problem),
     }
@@ -126,6 +144,43 @@ fn to_type_report<'a>(
         }
         Type::TApply(tapply, row, col) => to_tapply_report(alloc, filename, &tapply, *row, *col),
 
+        Type::TFunctionArgument(row, col) => match what_is_next(alloc.src_lines, *row, *col) {
+            Next::Other(Some(',')) => {
+                let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+                let region = Region::from_row_col(*row, *col);
+
+                let doc = alloc.stack(vec![
+                    alloc.reflow(r"I just started parsing a function argument type, but I encounterd two commas in a row:"),
+                    alloc.region_with_subregion(surroundings, region),
+                    alloc.concat(vec![alloc.reflow("Try removing one of them.")]),
+                ]);
+
+                Report {
+                    filename,
+                    doc,
+                    title: "DOUBLE COMMA".to_string(),
+                }
+            }
+            _ => todo!(),
+        },
+
+        Type::TStart(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+            let region = Region::from_row_col(*row, *col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I just started parsing a type, but I got stuck here:"),
+                alloc.region_with_subregion(surroundings, region),
+                alloc.note("I may be confused by indentation"),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "UNFINISHED TYPE".to_string(),
+            }
+        }
+
         Type::TIndentStart(row, col) => {
             let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
             let region = Region::from_row_col(*row, *col);
@@ -342,7 +397,7 @@ fn to_trecord_report<'a>(
         }
 
         TRecord::IndentEnd(row, col) => {
-            match next_line_starts_with_close_curly(alloc.src_lines, row - 1) {
+            match next_line_starts_with_close_curly(alloc.src_lines, row.saturating_sub(1)) {
                 Some((curly_row, curly_col)) => {
                     let surroundings =
                         Region::from_rows_cols(start_row, start_col, curly_row, curly_col);

compiler/reporting/tests/test_reporting.rs

@@ -4246,8 +4246,7 @@ mod test_reporting {
                 I am partway through parsing a record type, but I got stuck here:
                 
                 1│  f : {
-                2│  foo : I64,
+                         ^
-                    ^
                 
                 I was expecting to see a closing curly brace before this, so try
                 adding a } and see if that helps?
@@ -4589,8 +4588,115 @@ mod test_reporting {
                 I just started parsing an inline type alias, but I got stuck here:
                 
                 1│  f : I64 as 
-                2│  f = 0
+                              ^
-                    ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_double_comma() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64,,I64 -> I64 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── DOUBLE COMMA ────────────────────────────────────────────────────────────────
+                
+                I just started parsing a function argument type, but I encounterd two
+                commas in a row:
+                
+                1│  f : I64,,I64 -> I64 
+                            ^
+                
+                Try removing one of them.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_argument_no_arrow() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64, I64 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED TYPE ─────────────────────────────────────────────────────────────
+                
+                I just started parsing a type, but I got stuck here:
+                
+                1│  f : I64, I64 
+                                ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_argument_arrow_then_nothing() {
+        // TODO could do better by pointing out we're parsing a function type
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64, I64 -> 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED TYPE ─────────────────────────────────────────────────────────────
+                
+                I just started parsing a type, but I got stuck here:
+                
+                1│  f : I64, I64 -> 
+                                   ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn foobar() {
+        // TODO fix error on new row
+        // we should make whitespace only consumed when it puts us in a validly-indented position
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64 ->
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED TYPE ─────────────────────────────────────────────────────────────
+                
+                I just started parsing a type, but I got stuck here:
+                
+                1│  f : I64 ->
+                              ^
                 
                 Note: I may be confused by indentation
             "#