definite assignment: reading a local before it is initialized is a compile error (spec 4.1.5, b.1.9)

track linited per local alongside the ownership state; snapshots, exit records and joins carry it, and a join keeps a local set only when every reaching path set it. x = e, a declaration initializer, &x (out-parameter), a full array initializer, or using an aggregate as an address set a local; field and element writes do not set the aggregate. while/for bodies that may run zero times do not count; do/while does. compiler, runtime, std, actor and lsp sources initialize the locals the rule flagged; zc0 accepts = {} brace lists (zeroed). tests: tests/errors/uninit_*.zc, tests/conformance/4-statements/uninit_*.zc

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/lex.zc b/src/compiler/lex.zc
index 95415a6..3b810ba 100644
--- a/src/compiler/lex.zc
+++ b/src/compiler/lex.zc
@@ -377,7 +377,7 @@ int fieldscan(int n) {
 // before a program it joins to the runtime. the rest of the line is read here and the marker kept: the
 // source is read once to find the signatures and again to compile, and it counts only when compiling reaches it.
 int mark_line() {
-	char[300] b; int n = 0, i, base; word name;
+	char[300] b = {}; int n = 0, i, base; word name;
 	while (ch >= 0 && ch != 10) { if (n < 298) { b[n] = ch; n++; } nextch(); }
 	while (n && (b[n - 1] == 13 || b[n - 1] == 32)) n--;
 	b[n] = 0;