fail when end of input is not reached by parser

compiler/load/src/file.rs

@@ -3385,9 +3385,23 @@ fn parse<'a>(arena: &'a Bump, header: ModuleHeader<'a>) -> Result<Msg<'a>, Loadi
     let mut module_timing = header.module_timing;
     let parse_start = SystemTime::now();
     let parse_state = parser::State::new(&header.src, Attempting::Module);
-    let (parsed_defs, _) = module_defs()
-        .parse(&arena, parse_state)
-        .expect("TODO gracefully handle parse error on module defs. IMPORTANT: Bail out entirely if there are any BadUtf8 problems! That means the whole source file is not valid UTF-8 and any other errors we report may get mis-reported. We rely on this for safety in an `unsafe` block later on in this function.");
+    let parsed_defs = match module_defs().parse(&arena, parse_state) {
+        Ok((success, _state)) => success,
+        Err((fail, state)) => {
+            use roc_parse::parser::FailReason;
+            match fail.reason {
+                FailReason::BadUtf8 => panic!(
+                    r"TODO gracefully handle parse error on module defs. IMPORTANT: Bail out entirely if there are any BadUtf8 problems! That means the whole source file is not valid UTF-8 and any other errors we report may get mis-reported. We rely on this for safety in an `unsafe` block later on in this function."
+                ),
+                _ => panic!(
+                    "Parser Error\nmodule: {:?}\nattempting: {:?}\n(line, col): {:?}\n",
+                    header.module_id,
+                    fail.attempting,
+                    (state.line, state.column)
+                ),
+            }
+        }
+    };
 
     let parsed_defs = parsed_defs.into_bump_slice();
 

compiler/parse/src/module.rs

@@ -8,8 +8,8 @@ use crate::header::{
 };
 use crate::ident::{lowercase_ident, unqualified_ident, uppercase_ident};
 use crate::parser::{
-    self, ascii_char, ascii_string, loc, optional, peek_utf8_char, peek_utf8_char_at, unexpected,
-    unexpected_eof, Either, ParseResult, Parser, State,
+    self, ascii_char, ascii_string, end_of_file, loc, optional, peek_utf8_char, peek_utf8_char_at,
+    unexpected, unexpected_eof, Either, ParseResult, Parser, State,
 };
 use crate::string_literal;
 use crate::type_annotation;
@@ -290,7 +290,11 @@ pub fn platform_header<'a>() -> impl Parser<'a, PlatformHeader<'a>> {
 
 #[inline(always)]
 pub fn module_defs<'a>() -> impl Parser<'a, Vec<'a, Located<Def<'a>>>> {
-    zero_or_more!(space0_around(loc(def(0)), 0))
+    // this parses just the defs
+    let defs = zero_or_more!(space0_around(loc(def(0)), 0));
+
+    // but when parsing a file, we really want to reach the end of the file
+    skip_second!(defs, end_of_file())
 }
 
 struct ProvidesTo<'a> {

compiler/parse/src/parser.rs

@@ -75,6 +75,11 @@ impl<'a> State<'a> {
         self.original_len - self.bytes.len()
     }
 
+    /// Returns whether the parser has reached the end of the input
+    pub fn has_reached_end(&self) -> bool {
+        self.bytes.len() == 0
+    }
+
     /// Increments the line, then resets column, indent_col, and is_indenting.
     /// Advances the input by 1, to consume the newline character.
     pub fn newline(&self) -> Result<Self, (Fail, Self)> {
@@ -1278,3 +1283,18 @@ pub fn parse_utf8(bytes: &[u8]) -> Result<&str, FailReason> {
         Err(_) => Err(FailReason::BadUtf8),
     }
 }
+
+pub fn end_of_file<'a>() -> impl Parser<'a, ()> {
+    |_arena: &'a Bump, state: State<'a>| {
+        if state.has_reached_end() {
+            Ok(((), state))
+        } else {
+            let fail = Fail {
+                attempting: state.attempting,
+                reason: FailReason::ConditionFailed,
+            };
+
+            Err((fail, state))
+        }
+    }
+}

compiler/solve/tests/solve_expr.rs

@@ -854,7 +854,7 @@ mod solve_expr {
         infer_eq(
             indoc!(
                 r#"
-                    \f -> (\a, b -> f b a),
+                    \f -> (\a, b -> f b a)
                 "#
             ),
             "(a, b -> c) -> (b, a -> c)",