feat(parser): split plain statements on semicolons in the raw parse

Assisted-by: GLM 5.3 Flash

lexer/lexer_test.go

@@ -182,6 +182,19 @@ func TestNulIsIllegal(t *testing.T) {
 	eq(t, texts("MOVQ \x00 AX"), []string{"MOVQ", "\x00", "AX"})
 }
 
+func TestDivisionSlashInIdentifiers(t *testing.T) {
+	// U+2215 DIVISION SLASH is an identifier character, the way the
+	// toolchain's tokenizer treats it: the package path of a symbol is
+	// written with it (internal∕runtime∕atomic·Xchg) and must lex as one
+	// name.  The ordinary slash (U+002F) stays punctuation.
+	eq(t, texts("CALL internal∕runtime∕atomic·Xchg(SB)"),
+		[]string{"CALL", "internal∕runtime∕atomic·Xchg", "(", "SB", ")"})
+	eq(t, texts("MOVQ sync∕atomic·Align(SB), AX"),
+		[]string{"MOVQ", "sync∕atomic·Align", "(", "SB", ")", ",", "AX"})
+	// It may also begin a name, like any letter of the toolchain's rule.
+	eq(t, kinds("∕x"), []token.Kind{token.Ident})
+}
+
 // TestOffsetsAroundInvalidByte pins Position.Offset against the original
 // bytes: an invalid UTF-8 byte decodes to RuneError but advances the offset
 // table by exactly one byte, so every later position stays a true byte