AstGen: disable null bytes and empty stings in some places

Namely:
 * test names
 * identifiers
 * library names
 * import strings

1 files changed, 33 insertions, 0 deletions

diff --git a/test/cases/compile_errors/invalid_identifiers.zig b/test/cases/compile_errors/invalid_identifiers.zig
new file mode 100644
index 0000000000..bf1244b547
--- /dev/null
+++ b/test/cases/compile_errors/invalid_identifiers.zig
@@ -0,0 +1,33 @@
+extern "" var a: u32;
+extern "" fn b() void;
+
+extern "\x00" var c: u32;
+extern "\x00" fn d() void;
+
+test "" {}
+test "\x00" {}
+
+const e = @import("");
+const f = @import("\x00");
+
+comptime {
+    const @"" = undefined;
+}
+comptime {
+    const @"\x00" = undefined;
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :1:8: error: library name cannot be empty
+// :2:8: error: library name cannot be empty
+// :4:8: error: library name cannot contain null bytes
+// :5:8: error: library name cannot contain null bytes
+// :7:6: error: empty test name must be omitted
+// :8:6: error: test name cannot contain null bytes
+// :10:19: error: import path cannot be empty
+// :11:19: error: import path cannot contain null bytes
+// :14:11: error: identifier cannot be empty
+// :17:11: error: identifier cannot contain null bytes