From 6e97add1ee2b5cf3241308c17394fa3b76da37a2 Mon Sep 17 00:00:00 2001
From: Kampfkarren <boynedmaster@gmail.com>
Date: Wed, 27 Jul 2022 18:10:06 -0700
Subject: [PATCH] Support un-interpolated strings

---
 Ast/include/Luau/Lexer.h           |  4 +---
 Ast/src/Lexer.cpp                  | 27 +++++----------------------
 Ast/src/Parser.cpp                 |  5 -----
 tests/Parser.test.cpp              | 17 -----------------
 tests/conformance/stringinterp.lua |  8 ++++----
 5 files changed, 10 insertions(+), 51 deletions(-)

diff --git a/Ast/include/Luau/Lexer.h b/Ast/include/Luau/Lexer.h
index 428e247d..57877454 100644
--- a/Ast/include/Luau/Lexer.h
+++ b/Ast/include/Luau/Lexer.h
@@ -84,9 +84,7 @@ struct Lexeme
         BrokenString,
         BrokenComment,
         BrokenUnicode,
-
         BrokenInterpDoubleBrace,
-        BrokenInterpNoFormat,
 
         Error,
 
@@ -219,7 +217,7 @@ private:
     Lexeme readQuotedString();
 
     Lexeme readInterpolatedStringBegin();
-    std::optional<Lexeme> readInterpolatedStringSection(Position start, Lexeme::Type formatType);
+    Lexeme readInterpolatedStringSection(Position start, Lexeme::Type formatType, Lexeme::Type endType);
 
     void readBackslashInString();
 
diff --git a/Ast/src/Lexer.cpp b/Ast/src/Lexer.cpp
index 85064827..69b097db 100644
--- a/Ast/src/Lexer.cpp
+++ b/Ast/src/Lexer.cpp
@@ -189,9 +189,6 @@ std::string Lexeme::toString() const
     case BrokenInterpDoubleBrace:
         return "'{{', which is invalid (did you mean '\\{'?)";
 
-    case BrokenInterpNoFormat:
-        return "interpolated string with no formatting";
-
     case BrokenUnicode:
         if (codepoint)
         {
@@ -595,15 +592,7 @@ const Lexeme Lexer::nextInterpolatedString()
     Position start = position();
     unsigned int startOffset = offset;
 
-    if (std::optional<Lexeme> readSection = readInterpolatedStringSection(start, Lexeme::InterpStringMid))
-    {
-        lexeme = *readSection;
-        return lexeme;
-    }
-
-    consume();
-
-    lexeme = Lexeme(Location(start, position()), Lexeme::InterpStringEnd, &buffer[startOffset], offset - startOffset - 1);
+    lexeme = readInterpolatedStringSection(start, Lexeme::InterpStringMid, Lexeme::InterpStringEnd);
     return lexeme;
 }
 
@@ -612,17 +601,10 @@ Lexeme Lexer::readInterpolatedStringBegin()
     Position start = position();
     consume();
 
-    std::optional<Lexeme> readSectionOpt = readInterpolatedStringSection(start, Lexeme::InterpStringBegin);
-
-    if (!readSectionOpt)
-    {
-        return Lexeme(Location(start, position()), Lexeme::BrokenInterpNoFormat);
-    }
-
-    return *readSectionOpt;
+    return readInterpolatedStringSection(start, Lexeme::InterpStringBegin, Lexeme::QuotedString);
 }
 
-std::optional<Lexeme> Lexer::readInterpolatedStringSection(Position start, Lexeme::Type formatType)
+Lexeme Lexer::readInterpolatedStringSection(Position start, Lexeme::Type formatType, Lexeme::Type endType)
 {
     unsigned int startOffset = offset;
 
@@ -656,7 +638,8 @@ std::optional<Lexeme> Lexer::readInterpolatedStringSection(Position start, Lexem
         }
     }
 
-    return std::nullopt;
+    consume();
+    return Lexeme(Location(start, position()), endType, &buffer[startOffset], offset - startOffset - 1);
 }
 
 Lexeme Lexer::readNumber(const Position& start, unsigned int startOffset)
diff --git a/Ast/src/Parser.cpp b/Ast/src/Parser.cpp
index fd12ab0f..327cb167 100644
--- a/Ast/src/Parser.cpp
+++ b/Ast/src/Parser.cpp
@@ -2221,11 +2221,6 @@ AstExpr* Parser::parseSimpleExpr()
         nextLexeme();
         return reportExprError(start, {}, ERROR_INVALID_INTERP_DOUBLE_BRACE);
     }
-    else if (lexer.current().type == Lexeme::BrokenInterpNoFormat)
-    {
-        nextLexeme();
-        return reportExprError(start, {}, "Interpolated strings must contain expressions, and cannot be constant");
-    }
     else if (lexer.current().type == Lexeme::Dot3)
     {
         if (functionStack.back().vararg)
diff --git a/tests/Parser.test.cpp b/tests/Parser.test.cpp
index 5c34ebcd..5e0f6da4 100644
--- a/tests/Parser.test.cpp
+++ b/tests/Parser.test.cpp
@@ -1068,23 +1068,6 @@ TEST_CASE_FIXTURE(Fixture, "parse_interpolated_string_double_brace_mid")
     }
 }
 
-TEST_CASE_FIXTURE(Fixture, "parse_interpolated_string_without_format")
-{
-    ScopedFastFlag sff{"LuauInterpolatedStringBaseSupport", true};
-
-    try
-    {
-        parse(R"(
-            _ = `doge`
-        )");
-        FAIL("Expected ParseErrors to be thrown");
-    }
-    catch (const ParseErrors& e)
-    {
-        CHECK_EQ("Interpolated strings must contain expressions, and cannot be constant", e.getErrors().front().getMessage());
-    }
-}
-
 TEST_CASE_FIXTURE(Fixture, "parse_interpolated_string_without_end_brace")
 {
     ScopedFastFlag sff{"LuauInterpolatedStringBaseSupport", true};
diff --git a/tests/conformance/stringinterp.lua b/tests/conformance/stringinterp.lua
index cad3043c..2c79504a 100644
--- a/tests/conformance/stringinterp.lua
+++ b/tests/conformance/stringinterp.lua
@@ -31,10 +31,10 @@ assertEq(`This {localName} does not exist`, "This nil does not exist")
 assertEq(`Welcome to \
 {name}!`, "Welcome to \nLuau!")
 
-assertEq(`Escaped brace: \{} ({1})`, "Escaped brace: {} (1)")
-assertEq(`Backslash \ that escapes the space is not a part of the string... ({2})`, "Backslash  that escapes the space is not a part of the string... (2)")
-assertEq(`Escaped backslash \\ ({3})`, "Escaped backslash \\ (3)")
-assertEq(`Escaped backtick: \` ({4})`, "Escaped backtick: ` (4)")
+assertEq(`Escaped brace: \{}`, "Escaped brace: {}")
+assertEq(`Backslash \ that escapes the space is not a part of the string...`, "Backslash  that escapes the space is not a part of the string...")
+assertEq(`Escaped backslash \\`, "Escaped backslash \\")
+assertEq(`Escaped backtick: \``, "Escaped backtick: `")
 
 assertEq(`Hello {`from inside {"a nested string"}`}`, "Hello from inside a nested string")