From d8464c8f916cc8f5836bbf8c400bc3f9bf24501b Mon Sep 17 00:00:00 2001
From: Ayaz Hafiz <ayaz.hafiz.1@gmail.com>
Date: Mon, 29 Jun 2020 07:26:18 -0700
Subject: [PATCH] Use external float parser rather than rustc's

Per https://github.com/rust-lang/rust/issues/31407, rustc's float parser
may drop some valid float literals. For now use an external parser that
does not have these problems.

Closes #147
---
 libslide/Cargo.toml                               |   1 +
 libslide/src/scanner.rs                           |   5 ++++-
 ...MDA0ABowMDAwMDAwMC4wMDU1NTU1NTU1NTU1NTU1NTU1NT | Bin 0 -> 367 bytes
 slide/src/test/ui/giant_float.slide               |  14 ++++++++++++++
 4 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 slide/fuzz/seed/MTEAGjAwMDAwMDAwLjAwMDAxMQAaMDAwMDAwMDAuMDAwMDAwMDA0ABowMDAwMDAwMC4wMDAwMDAwMDAwMDA0ABowMDAwMDAwMC4wMDU1NTU1NTU1NTU1NTU1NTU1NT
 create mode 100644 slide/src/test/ui/giant_float.slide

diff --git a/libslide/Cargo.toml b/libslide/Cargo.toml
index 1f4e4fbdc..deaf5f108 100644
--- a/libslide/Cargo.toml
+++ b/libslide/Cargo.toml
@@ -26,6 +26,7 @@ required-features = ["benchmark-internals"]
 
 [dependencies]
 rug = "1.9.0"
+strtod = "0.0.1"
 
 [dependencies.num-traits]
 version = "0.2"
diff --git a/libslide/src/scanner.rs b/libslide/src/scanner.rs
index f1ce918d5..a02b4523a 100644
--- a/libslide/src/scanner.rs
+++ b/libslide/src/scanner.rs
@@ -1,6 +1,7 @@
 pub mod types;
 
 use crate::diagnostics::Diagnostic;
+use strtod::strtod;
 use types::TokenType as TT;
 pub use types::*;
 
@@ -123,7 +124,9 @@ impl Scanner {
             float_str.push(*self.next().unwrap());
             float_str.push_str(&self.collect_while(|c| c.is_digit(10)));
         }
-        let float = float_str.parse::<f64>().unwrap();
+        // TODO(https://github.com/rust-lang/rust/issues/31407): rustc's float parser may drop some
+        // valid float literals. For now, use an external parser.
+        let float = strtod(&float_str).unwrap();
 
         self.output.push(tok!(TT::Float(float), (start, self.pos)));
     }
diff --git a/slide/fuzz/seed/MTEAGjAwMDAwMDAwLjAwMDAxMQAaMDAwMDAwMDAuMDAwMDAwMDA0ABowMDAwMDAwMC4wMDAwMDAwMDAwMDA0ABowMDAwMDAwMC4wMDU1NTU1NTU1NTU1NTU1NTU1NT b/slide/fuzz/seed/MTEAGjAwMDAwMDAwLjAwMDAxMQAaMDAwMDAwMDAuMDAwMDAwMDA0ABowMDAwMDAwMC4wMDAwMDAwMDAwMDA0ABowMDAwMDAwMC4wMDU1NTU1NTU1NTU1NTU1NTU1NT
new file mode 100644
index 0000000000000000000000000000000000000000..c03c5f986f66587a4c179e74f9884e5ff733dc09
GIT binary patch
literal 367
zcmXpsWRNm|0zD9Ih%NvUG(l4Y5(5ELaZ@Y+qRxO8Mq{xJS;z#LLnIsGS^|p6H`qi5
E06ITL;Q#;t

literal 0
HcmV?d00001

diff --git a/slide/src/test/ui/giant_float.slide b/slide/src/test/ui/giant_float.slide
new file mode 100644
index 000000000..af8db5ac9
--- /dev/null
+++ b/slide/src/test/ui/giant_float.slide
@@ -0,0 +1,14 @@
+===in
+000000000.0055555555555555555555000005555555555555555555455555555555555555555555555555555555555555550000005555555555555555555555555555555455555555555555555555555555555555555555555555550000004
+===in
+
+~~~stdout
+0.005555555555555556
+~~~stdout
+
+~~~stderr
+~~~stderr
+
+~~~exitcode
+0
+~~~exitcode