fastfloat: strconv inequivalence - ParseFloat64("8.54E-4") got = 0.0008539999999999999, want 0.000854 about fastjson HOT 1 OPEN

diff --git a/fastfloat/parse.go b/fastfloat/parse.go
index b37838d..b8a0bbe 100644
--- a/fastfloat/parse.go
+++ b/fastfloat/parse.go
@@ -500,6 +500,15 @@ func Parse(s string) (float64, error) {
 		if expMinus {
 			exp = -exp
 		}
+		if d != uint64(f) {
+			// TODO comment.
+			// Fall back to standard parsing.
+			f, err := strconv.ParseFloat(s, 64)
+			if err != nil && !math.IsInf(f, 0) {
+				return 0, fmt.Errorf("cannot parse exponent in %q: %s", s, err)
+			}
+			return f, nil
+		}
 		f *= math.Pow10(int(exp))
 		if i >= uint(len(s)) {
 			if minus {
diff --git a/fastfloat/parse_test.go b/fastfloat/parse_test.go
index e4dfe2f..e06912a 100644
--- a/fastfloat/parse_test.go
+++ b/fastfloat/parse_test.go
@@ -445,6 +445,7 @@ func TestParseSuccess(t *testing.T) {
 	f("-123e456", math.Inf(-1)) // too big exponent
 	f("1e4", 1e4)
 	f("-1E-10", -1e-10)
+	f("8.54E-4", 8.54e-4)
 
 	// Fractional + exponent part
 	f("0.123e4", 0.123e4)