Merge commit '3b7c7f97e4a7bb253a8d398ee4f8346f6cf2817b' into sync-from-ra

21 files changed, 566 insertions, 33 deletions

diff --git a/crates/parser/Cargo.toml b/crates/parser/Cargo.toml
index 09e62c35278..efb326323f9 100644
--- a/crates/parser/Cargo.toml
+++ b/crates/parser/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 
 [dependencies]
 drop_bomb = "0.1.5"
-rustc_lexer.workspace = true
+rustc-dependencies.workspace = true
 
 limit.workspace = true
 
@@ -22,3 +22,6 @@ expect-test = "1.4.0"
 
 stdx.workspace = true
 sourcegen.workspace = true
+
+[features]
+in-rust-tree = ["rustc-dependencies/in-rust-tree"]
diff --git a/crates/parser/src/grammar/params.rs b/crates/parser/src/grammar/params.rs
index 74eae9151a2..846da28cb01 100644
--- a/crates/parser/src/grammar/params.rs
+++ b/crates/parser/src/grammar/params.rs
@@ -7,6 +7,9 @@ use super::*;
 // fn b(x: i32) {}
 // fn c(x: i32, ) {}
 // fn d(x: i32, y: ()) {}
+
+// test_err empty_param_slot
+// fn f(y: i32, ,t: i32) {}
 pub(super) fn param_list_fn_def(p: &mut Parser<'_>) {
     list_(p, Flavor::FnDef);
 }
@@ -71,7 +74,11 @@ fn list_(p: &mut Parser<'_>, flavor: Flavor) {
         if !p.at_ts(PARAM_FIRST.union(ATTRIBUTE_FIRST)) {
             p.error("expected value parameter");
             m.abandon(p);
-            break;
+            if p.eat(T![,]) {
+                continue;
+            } else {
+                break;
+            }
         }
         param(p, m, flavor);
         if !p.at(T![,]) {
diff --git a/crates/parser/src/lexed_str.rs b/crates/parser/src/lexed_str.rs
index 36c52953a02..b9e7566fdf9 100644
--- a/crates/parser/src/lexed_str.rs
+++ b/crates/parser/src/lexed_str.rs
@@ -8,8 +8,12 @@
 //! Note that these tokens, unlike the tokens we feed into the parser, do
 //! include info about comments and whitespace.
 
+use rustc_dependencies::lexer as rustc_lexer;
+
 use std::ops;
 
+use rustc_lexer::unescape::{EscapeError, Mode};
+
 use crate::{
     SyntaxKind::{self, *},
     T,
@@ -253,30 +257,60 @@ impl<'a> Converter<'a> {
             rustc_lexer::LiteralKind::Char { terminated } => {
                 if !terminated {
                     err = "Missing trailing `'` symbol to terminate the character literal";
+                } else {
+                    let text = &self.res.text[self.offset + 1..][..len - 1];
+                    let i = text.rfind('\'').unwrap();
+                    let text = &text[..i];
+                    if let Err(e) = rustc_lexer::unescape::unescape_char(text) {
+                        err = error_to_diagnostic_message(e, Mode::Char);
+                    }
                 }
                 CHAR
             }
             rustc_lexer::LiteralKind::Byte { terminated } => {
                 if !terminated {
                     err = "Missing trailing `'` symbol to terminate the byte literal";
+                } else {
+                    let text = &self.res.text[self.offset + 2..][..len - 2];
+                    let i = text.rfind('\'').unwrap();
+                    let text = &text[..i];
+                    if let Err(e) = rustc_lexer::unescape::unescape_byte(text) {
+                        err = error_to_diagnostic_message(e, Mode::Byte);
+                    }
                 }
+
                 BYTE
             }
             rustc_lexer::LiteralKind::Str { terminated } => {
                 if !terminated {
                     err = "Missing trailing `\"` symbol to terminate the string literal";
+                } else {
+                    let text = &self.res.text[self.offset + 1..][..len - 1];
+                    let i = text.rfind('"').unwrap();
+                    let text = &text[..i];
+                    err = unescape_string_error_message(text, Mode::Str);
                 }
                 STRING
             }
             rustc_lexer::LiteralKind::ByteStr { terminated } => {
                 if !terminated {
                     err = "Missing trailing `\"` symbol to terminate the byte string literal";
+                } else {
+                    let text = &self.res.text[self.offset + 2..][..len - 2];
+                    let i = text.rfind('"').unwrap();
+                    let text = &text[..i];
+                    err = unescape_string_error_message(text, Mode::ByteStr);
                 }
                 BYTE_STRING
             }
             rustc_lexer::LiteralKind::CStr { terminated } => {
                 if !terminated {
                     err = "Missing trailing `\"` symbol to terminate the string literal";
+                } else {
+                    let text = &self.res.text[self.offset + 2..][..len - 2];
+                    let i = text.rfind('"').unwrap();
+                    let text = &text[..i];
+                    err = unescape_string_error_message(text, Mode::CStr);
                 }
                 C_STRING
             }
@@ -304,3 +338,64 @@ impl<'a> Converter<'a> {
         self.push(syntax_kind, len, err);
     }
 }
+
+fn error_to_diagnostic_message(error: EscapeError, mode: Mode) -> &'static str {
+    match error {
+        EscapeError::ZeroChars => "empty character literal",
+        EscapeError::MoreThanOneChar => "character literal may only contain one codepoint",
+        EscapeError::LoneSlash => "",
+        EscapeError::InvalidEscape if mode == Mode::Byte || mode == Mode::ByteStr => {
+            "unknown byte escape"
+        }
+        EscapeError::InvalidEscape => "unknown character escape",
+        EscapeError::BareCarriageReturn => "",
+        EscapeError::BareCarriageReturnInRawString => "",
+        EscapeError::EscapeOnlyChar if mode == Mode::Byte => "byte constant must be escaped",
+        EscapeError::EscapeOnlyChar => "character constant must be escaped",
+        EscapeError::TooShortHexEscape => "numeric character escape is too short",
+        EscapeError::InvalidCharInHexEscape => "invalid character in numeric character escape",
+        EscapeError::OutOfRangeHexEscape => "out of range hex escape",
+        EscapeError::NoBraceInUnicodeEscape => "incorrect unicode escape sequence",
+        EscapeError::InvalidCharInUnicodeEscape => "invalid character in unicode escape",
+        EscapeError::EmptyUnicodeEscape => "empty unicode escape",
+        EscapeError::UnclosedUnicodeEscape => "unterminated unicode escape",
+        EscapeError::LeadingUnderscoreUnicodeEscape => "invalid start of unicode escape",
+        EscapeError::OverlongUnicodeEscape => "overlong unicode escape",
+        EscapeError::LoneSurrogateUnicodeEscape => "invalid unicode character escape",
+        EscapeError::OutOfRangeUnicodeEscape => "invalid unicode character escape",
+        EscapeError::UnicodeEscapeInByte => "unicode escape in byte string",
+        EscapeError::NonAsciiCharInByte if mode == Mode::Byte => {
+            "non-ASCII character in byte literal"
+        }
+        EscapeError::NonAsciiCharInByte if mode == Mode::ByteStr => {
+            "non-ASCII character in byte string literal"
+        }
+        EscapeError::NonAsciiCharInByte => "non-ASCII character in raw byte string literal",
+        EscapeError::UnskippedWhitespaceWarning => "",
+        EscapeError::MultipleSkippedLinesWarning => "",
+    }
+}
+
+fn unescape_string_error_message(text: &str, mode: Mode) -> &'static str {
+    let mut error_message = "";
+    match mode {
+        Mode::CStr => {
+            rustc_lexer::unescape::unescape_c_string(text, mode, &mut |_, res| {
+                if let Err(e) = res {
+                    error_message = error_to_diagnostic_message(e, mode);
+                }
+            });
+        }
+        Mode::ByteStr | Mode::Str => {
+            rustc_lexer::unescape::unescape_literal(text, mode, &mut |_, res| {
+                if let Err(e) = res {
+                    error_message = error_to_diagnostic_message(e, mode);
+                }
+            });
+        }
+        _ => {
+            // Other Modes are not supported yet or do not apply
+        }
+    }
+    error_message
+}
diff --git a/crates/parser/src/lib.rs b/crates/parser/src/lib.rs
index c155e8aaf67..fcfd1a50719 100644
--- a/crates/parser/src/lib.rs
+++ b/crates/parser/src/lib.rs
@@ -19,6 +19,7 @@
 
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
 #![allow(rustdoc::private_intra_doc_links)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 mod lexed_str;
 mod token_set;
diff --git a/crates/parser/src/shortcuts.rs b/crates/parser/src/shortcuts.rs
index 2c47e3d086d..57005a6834c 100644
--- a/crates/parser/src/shortcuts.rs
+++ b/crates/parser/src/shortcuts.rs
@@ -32,29 +32,27 @@ impl LexedStr<'_> {
             let kind = self.kind(i);
             if kind.is_trivia() {
                 was_joint = false
+            } else if kind == SyntaxKind::IDENT {
+                let token_text = self.text(i);
+                let contextual_kw =
+                    SyntaxKind::from_contextual_keyword(token_text).unwrap_or(SyntaxKind::IDENT);
+                res.push_ident(contextual_kw);
             } else {
-                if kind == SyntaxKind::IDENT {
-                    let token_text = self.text(i);
-                    let contextual_kw = SyntaxKind::from_contextual_keyword(token_text)
-                        .unwrap_or(SyntaxKind::IDENT);
-                    res.push_ident(contextual_kw);
-                } else {
-                    if was_joint {
+                if was_joint {
+                    res.was_joint();
+                }
+                res.push(kind);
+                // Tag the token as joint if it is float with a fractional part
+                // we use this jointness to inform the parser about what token split
+                // event to emit when we encounter a float literal in a field access
+                if kind == SyntaxKind::FLOAT_NUMBER {
+                    if !self.text(i).ends_with('.') {
                         res.was_joint();
-                    }
-                    res.push(kind);
-                    // Tag the token as joint if it is float with a fractional part
-                    // we use this jointness to inform the parser about what token split
-                    // event to emit when we encounter a float literal in a field access
-                    if kind == SyntaxKind::FLOAT_NUMBER {
-                        if !self.text(i).ends_with('.') {
-                            res.was_joint();
-                        } else {
-                            was_joint = false;
-                        }
                     } else {
-                        was_joint = true;
+                        was_joint = false;
                     }
+                } else {
+                    was_joint = true;
                 }
             }
         }
diff --git a/crates/parser/test_data/lexer/err/byte_char_literals.rast b/crates/parser/test_data/lexer/err/byte_char_literals.rast
new file mode 100644
index 00000000000..7603c9099da
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/byte_char_literals.rast
@@ -0,0 +1,86 @@
+BYTE "b''" error: empty character literal
+WHITESPACE "\n"
+BYTE "b'\\'" error: Missing trailing `'` symbol to terminate the byte literal
+WHITESPACE "\n"
+BYTE "b'\n'" error: byte constant must be escaped
+WHITESPACE "\n"
+BYTE "b'spam'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\x0ff'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\\"a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\na'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\ra'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\ta'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\\\a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\'a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\0a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\u{0}x'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{1F63b}}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\v'" error: unknown byte escape
+WHITESPACE "\n"
+BYTE "b'\\💩'" error: unknown byte escape
+WHITESPACE "\n"
+BYTE "b'\\●'" error: unknown byte escape
+WHITESPACE "\n"
+BYTE "b'\\\\\\r'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+BYTE "b'\\x'" error: numeric character escape is too short
+WHITESPACE "\n"
+BYTE "b'\\x0'" error: numeric character escape is too short
+WHITESPACE "\n"
+BYTE "b'\\xf'" error: numeric character escape is too short
+WHITESPACE "\n"
+BYTE "b'\\xa'" error: numeric character escape is too short
+WHITESPACE "\n"
+BYTE "b'\\xx'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+BYTE "b'\\xы'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+BYTE "b'\\x🦀'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+BYTE "b'\\xtt'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+BYTE "b'\\u'" error: incorrect unicode escape sequence
+WHITESPACE "\n"
+BYTE "b'\\u[0123]'" error: incorrect unicode escape sequence
+WHITESPACE "\n"
+BYTE "b'\\u{0x}'" error: invalid character in unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{'" error: unterminated unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{0000'" error: unterminated unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{}'" error: empty unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{_0000}'" error: invalid start of unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{0000000}'" error: overlong unicode escape
+WHITESPACE "\n"
+BYTE "b'\\u{FFFFFF}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{ffffff}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{ffffff}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{DC00}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{DDDD}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{DFFF}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{D800}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{DAAA}'" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE "b'\\u{DBFF}'" error: unicode escape in byte string
+WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/err/byte_char_literals.rs b/crates/parser/test_data/lexer/err/byte_char_literals.rs
new file mode 100644
index 00000000000..b2d06e490bd
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/byte_char_literals.rs
@@ -0,0 +1,44 @@
+b''
+b'\'
+b'
+'
+b'spam'
+b'\x0ff'
+b'\"a'
+b'\na'
+b'\ra'
+b'\ta'
+b'\\a'
+b'\'a'
+b'\0a'
+b'\u{0}x'
+b'\u{1F63b}}'
+b'\v'
+b'\💩'
+b'\●'
+b'\\\r'
+b'\x'
+b'\x0'
+b'\xf'
+b'\xa'
+b'\xx'
+b'\xы'
+b'\x🦀'
+b'\xtt'
+b'\u'
+b'\u[0123]'
+b'\u{0x}'
+b'\u{'
+b'\u{0000'
+b'\u{}'
+b'\u{_0000}'
+b'\u{0000000}'
+b'\u{FFFFFF}'
+b'\u{ffffff}'
+b'\u{ffffff}'
+b'\u{DC00}'
+b'\u{DDDD}'
+b'\u{DFFF}'
+b'\u{D800}'
+b'\u{DAAA}'
+b'\u{DBFF}'
diff --git a/crates/parser/test_data/lexer/err/byte_strings.rast b/crates/parser/test_data/lexer/err/byte_strings.rast
new file mode 100644
index 00000000000..e8d8ff8cefb
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/byte_strings.rast
@@ -0,0 +1,28 @@
+BYTE_STRING "b\"\\💩\"" error: unknown byte escape
+WHITESPACE "\n"
+BYTE_STRING "b\"\\●\"" error: unknown byte escape
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{_0000}\"" error: invalid start of unicode escape
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{0000000}\"" error: overlong unicode escape
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{FFFFFF}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{ffffff}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{ffffff}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{DC00}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{DDDD}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{DFFF}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{D800}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{DAAA}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\u{DBFF}\"" error: unicode escape in byte string
+WHITESPACE "\n"
+BYTE_STRING "b\"\\xы\"" error: invalid character in numeric character escape
+WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/err/byte_strings.rs b/crates/parser/test_data/lexer/err/byte_strings.rs
new file mode 100644
index 00000000000..e74847137b1
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/byte_strings.rs
@@ -0,0 +1,14 @@
+b"\💩"
+b"\●"
+b"\u{_0000}"
+b"\u{0000000}"
+b"\u{FFFFFF}"
+b"\u{ffffff}"
+b"\u{ffffff}"
+b"\u{DC00}"
+b"\u{DDDD}"
+b"\u{DFFF}"
+b"\u{D800}"
+b"\u{DAAA}"
+b"\u{DBFF}"
+b"\xы"
diff --git a/crates/parser/test_data/lexer/err/c_strings.rast b/crates/parser/test_data/lexer/err/c_strings.rast
new file mode 100644
index 00000000000..1b4424ba5c7
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/c_strings.rast
@@ -0,0 +1,28 @@
+C_STRING "c\"\\💩\"" error: unknown character escape
+WHITESPACE "\n"
+C_STRING "c\"\\●\"" error: unknown character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{_0000}\"" error: invalid start of unicode escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{0000000}\"" error: overlong unicode escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{FFFFFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{ffffff}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{ffffff}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{DC00}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{DDDD}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{DFFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{D800}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{DAAA}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\u{DBFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+C_STRING "c\"\\xы\"" error: invalid character in numeric character escape
+WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/err/c_strings.rs b/crates/parser/test_data/lexer/err/c_strings.rs
new file mode 100644
index 00000000000..1b78ffc28a0
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/c_strings.rs
@@ -0,0 +1,14 @@
+c"\💩"
+c"\●"
+c"\u{_0000}"
+c"\u{0000000}"
+c"\u{FFFFFF}"
+c"\u{ffffff}"
+c"\u{ffffff}"
+c"\u{DC00}"
+c"\u{DDDD}"
+c"\u{DFFF}"
+c"\u{D800}"
+c"\u{DAAA}"
+c"\u{DBFF}"
+c"\xы"
diff --git a/crates/parser/test_data/lexer/err/char_literals.rast b/crates/parser/test_data/lexer/err/char_literals.rast
new file mode 100644
index 00000000000..b1e1364d4c2
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/char_literals.rast
@@ -0,0 +1,92 @@
+CHAR "'hello'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "''" error: empty character literal
+WHITESPACE "\n"
+CHAR "'\n'" error: character constant must be escaped
+WHITESPACE "\n"
+CHAR "'spam'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\x0ff'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\\"a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\na'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\ra'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\ta'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\\\a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\'a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\0a'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\u{0}x'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\u{1F63b}}'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\v'" error: unknown character escape
+WHITESPACE "\n"
+CHAR "'\\💩'" error: unknown character escape
+WHITESPACE "\n"
+CHAR "'\\●'" error: unknown character escape
+WHITESPACE "\n"
+CHAR "'\\\\\\r'" error: character literal may only contain one codepoint
+WHITESPACE "\n"
+CHAR "'\\x'" error: numeric character escape is too short
+WHITESPACE "\n"
+CHAR "'\\x0'" error: numeric character escape is too short
+WHITESPACE "\n"
+CHAR "'\\xf'" error: numeric character escape is too short
+WHITESPACE "\n"
+CHAR "'\\xa'" error: numeric character escape is too short
+WHITESPACE "\n"
+CHAR "'\\xx'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+CHAR "'\\xы'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+CHAR "'\\x🦀'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+CHAR "'\\xtt'" error: invalid character in numeric character escape
+WHITESPACE "\n"
+CHAR "'\\xff'" error: out of range hex escape
+WHITESPACE "\n"
+CHAR "'\\xFF'" error: out of range hex escape
+WHITESPACE "\n"
+CHAR "'\\x80'" error: out of range hex escape
+WHITESPACE "\n"
+CHAR "'\\u'" error: incorrect unicode escape sequence
+WHITESPACE "\n"
+CHAR "'\\u[0123]'" error: incorrect unicode escape sequence
+WHITESPACE "\n"
+CHAR "'\\u{0x}'" error: invalid character in unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{'" error: unterminated unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{0000'" error: unterminated unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{}'" error: empty unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{_0000}'" error: invalid start of unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{0000000}'" error: overlong unicode escape
+WHITESPACE "\n"
+CHAR "'\\u{FFFFFF}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{ffffff}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{ffffff}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{DC00}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{DDDD}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{DFFF}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{D800}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{DAAA}'" error: invalid unicode character escape
+WHITESPACE "\n"
+CHAR "'\\u{DBFF}'" error: invalid unicode character escape
+WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/err/char_literals.rs b/crates/parser/test_data/lexer/err/char_literals.rs
new file mode 100644
index 00000000000..291f99d8020
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/char_literals.rs
@@ -0,0 +1,47 @@
+'hello'
+''
+'
+'
+'spam'
+'\x0ff'
+'\"a'
+'\na'
+'\ra'
+'\ta'
+'\\a'
+'\'a'
+'\0a'
+'\u{0}x'
+'\u{1F63b}}'
+'\v'
+'\💩'
+'\●'
+'\\\r'
+'\x'
+'\x0'
+'\xf'
+'\xa'
+'\xx'
+'\xы'
+'\x🦀'
+'\xtt'
+'\xff'
+'\xFF'
+'\x80'
+'\u'
+'\u[0123]'
+'\u{0x}'
+'\u{'
+'\u{0000'
+'\u{}'
+'\u{_0000}'
+'\u{0000000}'
+'\u{FFFFFF}'
+'\u{ffffff}'
+'\u{ffffff}'
+'\u{DC00}'
+'\u{DDDD}'
+'\u{DFFF}'
+'\u{D800}'
+'\u{DAAA}'
+'\u{DBFF}'
diff --git a/crates/parser/test_data/lexer/err/strings.rast b/crates/parser/test_data/lexer/err/strings.rast
new file mode 100644
index 00000000000..0cd1747208e
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/strings.rast
@@ -0,0 +1,28 @@
+STRING "\"\\💩\"" error: unknown character escape
+WHITESPACE "\n"
+STRING "\"\\●\"" error: unknown character escape
+WHITESPACE "\n"
+STRING "\"\\u{_0000}\"" error: invalid start of unicode escape
+WHITESPACE "\n"
+STRING "\"\\u{0000000}\"" error: overlong unicode escape
+WHITESPACE "\n"
+STRING "\"\\u{FFFFFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{ffffff}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{ffffff}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{DC00}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{DDDD}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{DFFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{D800}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{DAAA}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\u{DBFF}\"" error: invalid unicode character escape
+WHITESPACE "\n"
+STRING "\"\\xы\"" error: invalid character in numeric character escape
+WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/err/strings.rs b/crates/parser/test_data/lexer/err/strings.rs
new file mode 100644
index 00000000000..2499516d3fa
--- /dev/null
+++ b/crates/parser/test_data/lexer/err/strings.rs
@@ -0,0 +1,14 @@
+"\💩"
+"\●"
+"\u{_0000}"
+"\u{0000000}"
+"\u{FFFFFF}"
+"\u{ffffff}"
+"\u{ffffff}"
+"\u{DC00}"
+"\u{DDDD}"
+"\u{DFFF}"
+"\u{D800}"
+"\u{DAAA}"
+"\u{DBFF}"
+"\xы"
diff --git a/crates/parser/test_data/lexer/ok/byte_strings.rast b/crates/parser/test_data/lexer/ok/byte_strings.rast
index c848ac368e4..fd20ca57ac6 100644
--- a/crates/parser/test_data/lexer/ok/byte_strings.rast
+++ b/crates/parser/test_data/lexer/ok/byte_strings.rast
@@ -1,13 +1,9 @@
-BYTE "b''"
-WHITESPACE " "
 BYTE "b'x'"
 WHITESPACE " "
 BYTE_STRING "b\"foo\""
 WHITESPACE " "
 BYTE_STRING "br\"\""
 WHITESPACE "\n"
-BYTE "b''suf"
-WHITESPACE " "
 BYTE_STRING "b\"\"ix"
 WHITESPACE " "
 BYTE_STRING "br\"\"br"
@@ -17,6 +13,4 @@ WHITESPACE " "
 BYTE "b'\\\\'"
 WHITESPACE " "
 BYTE "b'\\''"
-WHITESPACE " "
-BYTE "b'hello'"
 WHITESPACE "\n"
diff --git a/crates/parser/test_data/lexer/ok/byte_strings.rs b/crates/parser/test_data/lexer/ok/byte_strings.rs
index b54930f5e69..65460d02cb2 100644
--- a/crates/parser/test_data/lexer/ok/byte_strings.rs
+++ b/crates/parser/test_data/lexer/ok/byte_strings.rs
@@ -1,3 +1,3 @@
-b'' b'x' b"foo" br""
-b''suf b""ix br""br
-b'\n' b'\\' b'\'' b'hello'
+b'x' b"foo" br""
+b""ix br""br
+b'\n' b'\\' b'\''
diff --git a/crates/parser/test_data/lexer/ok/chars.rast b/crates/parser/test_data/lexer/ok/chars.rast
index 66e58cc298f..07172a4ecc0 100644
--- a/crates/parser/test_data/lexer/ok/chars.rast
+++ b/crates/parser/test_data/lexer/ok/chars.rast
@@ -4,8 +4,6 @@ CHAR "' '"
 WHITESPACE " "
 CHAR "'0'"
 WHITESPACE " "
-CHAR "'hello'"
-WHITESPACE " "
 CHAR "'\\x7f'"
 WHITESPACE " "
 CHAR "'\\n'"
diff --git a/crates/parser/test_data/lexer/ok/chars.rs b/crates/parser/test_data/lexer/ok/chars.rs
index 454ee0a5f61..15f52c113c1 100644
--- a/crates/parser/test_data/lexer/ok/chars.rs
+++ b/crates/parser/test_data/lexer/ok/chars.rs
@@ -1 +1 @@
-'x' ' ' '0' 'hello' '\x7f' '\n' '\\' '\''
+'x' ' ' '0' '\x7f' '\n' '\\' '\''
diff --git a/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rast b/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rast
new file mode 100644
index 00000000000..39e35a81ee2
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rast
@@ -0,0 +1,41 @@
+SOURCE_FILE
+  FN
+    FN_KW "fn"
+    WHITESPACE " "
+    NAME
+      IDENT "f"
+    PARAM_LIST
+      L_PAREN "("
+      PARAM
+        IDENT_PAT
+          NAME
+            IDENT "y"
+        COLON ":"
+        WHITESPACE " "
+        PATH_TYPE
+          PATH
+            PATH_SEGMENT
+              NAME_REF
+                IDENT "i32"
+      COMMA ","
+      WHITESPACE " "
+      COMMA ","
+      PARAM
+        IDENT_PAT
+          NAME
+            IDENT "t"
+        COLON ":"
+        WHITESPACE " "
+        PATH_TYPE
+          PATH
+            PATH_SEGMENT
+              NAME_REF
+                IDENT "i32"
+      R_PAREN ")"
+    WHITESPACE " "
+    BLOCK_EXPR
+      STMT_LIST
+        L_CURLY "{"
+        R_CURLY "}"
+  WHITESPACE "\n"
+error 12: expected value parameter
diff --git a/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rs b/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rs
new file mode 100644
index 00000000000..0adf7b8d2f0
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/err/0023_empty_param_slot.rs
@@ -0,0 +1 @@
+fn f(y: i32, ,t: i32) {}