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

5 files changed, 52 insertions, 0 deletions

diff --git a/tests/errors/uninit_branch.zc b/tests/errors/uninit_branch.zc
new file mode 100644
index 0000000..e4d253b
--- /dev/null
+++ b/tests/errors/uninit_branch.zc
@@ -0,0 +1,10 @@
+namespace;
+include rt;
+
+// expect: x: used before it is initialized
+fn main() {
+	int x;
+	if (rt.get_c()) x = 1;
+	rt.put_n(x);
+	return 0;
+}
diff --git a/tests/errors/uninit_loop.zc b/tests/errors/uninit_loop.zc
new file mode 100644
index 0000000..d345296
--- /dev/null
+++ b/tests/errors/uninit_loop.zc
@@ -0,0 +1,11 @@
+namespace;
+include rt;
+
+// expect: x: used before it is initialized
+fn main() {
+	int x;
+	int n = 0;
+	while (n) { x = 1; n = 0; }
+	rt.put_n(x);
+	return 0;
+}
diff --git a/tests/errors/uninit_partial_array.zc b/tests/errors/uninit_partial_array.zc
new file mode 100644
index 0000000..d30310f
--- /dev/null
+++ b/tests/errors/uninit_partial_array.zc
@@ -0,0 +1,10 @@
+namespace;
+include rt;
+
+// expect: a: used before it is initialized
+fn main() {
+	int[4] a;
+	a[0] = 1;
+	rt.put_n(a[1]);
+	return 0;
+}
diff --git a/tests/errors/uninit_partial_struct.zc b/tests/errors/uninit_partial_struct.zc
new file mode 100644
index 0000000..7b65481
--- /dev/null
+++ b/tests/errors/uninit_partial_struct.zc
@@ -0,0 +1,12 @@
+namespace;
+include rt;
+
+struct point { int x; int y; }
+
+// expect: p: used before it is initialized
+fn main() {
+	point p;
+	p.x = 1;
+	rt.put_n(p.y);
+	return 0;
+}
diff --git a/tests/errors/uninit_read.zc b/tests/errors/uninit_read.zc
new file mode 100644
index 0000000..3a18a95
--- /dev/null
+++ b/tests/errors/uninit_read.zc
@@ -0,0 +1,9 @@
+namespace;
+include rt;
+
+// expect: x: used before it is initialized
+fn main() {
+	int x;
+	rt.put_n(x);
+	return 0;
+}