err on dot in exponent while scanning numbers

zephyrtronium · zephyrtronium · commit 7c25b7bca48d · 2022-03-25T21:57:59.000-04:00
diff --git a/lex.go b/lex.go
@@ -244,7 +244,7 @@ func (l *lexer) scanNum() error {
 		l.buf.WriteRune(r)
 		switch r {
 		case '.':
-			if dot {
+			if dot || e {
 				return l.error("number")
 			}
 			dot = true
diff --git a/lex_test.go b/lex_test.go
@@ -66,6 +66,8 @@ func TestLex(t *testing.T) {
 		{"0$", []lexToken{{pos: 1}, {kind: tokenEOF, pos: 3}}, 1},
 		{"$0", []lexToken{{pos: 1}, {text: "0", kind: tokenNum, pos: 2}, {kind: tokenEOF, pos: 3}}, 1},
 		{"$$", []lexToken{{pos: 1}, {pos: 2}, {kind: tokenEOF, pos: 3}}, 2},
+		// cases identified with fuzzing
+		{"0E0.", []lexToken{{pos: 1}, {kind: tokenEOF, pos: 5}}, 1},
 	}
 
 	for _, c := range cases {
diff --git a/testdata/fuzz/FuzzEval/5bd6ba944db58ead9a3d53f8067e391fb0c9f0073e162e6544ddb767f17575c5 b/testdata/fuzz/FuzzEval/5bd6ba944db58ead9a3d53f8067e391fb0c9f0073e162e6544ddb767f17575c5
@@ -0,0 +1,2 @@
+go test fuzz v1
+string("0E00.")

Original file line number	Diff line number	Diff line change
`@@ -66,6 +66,8 @@ func TestLex(t *testing.T) {`
`66`	`66`	`{"0$", []lexToken{{pos: 1}, {kind: tokenEOF, pos: 3}}, 1},`
`67`	`67`	`{"$0", []lexToken{{pos: 1}, {text: "0", kind: tokenNum, pos: 2}, {kind: tokenEOF, pos: 3}}, 1},`
`68`	`68`	`{"$$", []lexToken{{pos: 1}, {pos: 2}, {kind: tokenEOF, pos: 3}}, 2},`
	`69`	`+ // cases identified with fuzzing`
	`70`	`+ {"0E0.", []lexToken{{pos: 1}, {kind: tokenEOF, pos: 5}}, 1},`
`69`	`71`	`}`
`70`	`72`
`71`	`73`	`for _, c := range cases {`