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, 4 insertions, 4 deletions

diff --git a/src/runtime/rt.zc b/src/runtime/rt.zc
index 4f96320..a79387f 100644
--- a/src/runtime/rt.zc
+++ b/src/runtime/rt.zc
@@ -182,7 +182,7 @@ int put_s(char* s) {
 // write the decimal form of a number, with a minus sign for a negative one.
 // the smallest integer is handled as its own case.
 int put_n(int n) {
-	char[24] b; int i = 0;
+	char[24] b = {}; int i = 0;
 	if (n < 0) { put_c('-'); n = 0 - n; }
 	if (n < 0) { put_s("9223372036854775808"); return 0; }
 	while (1) { b[i++] = '0' + n % 10; n = n / 10; if (!n) break; }
@@ -340,7 +340,7 @@ int s_to_n(bstr s) {
 }
 // a new packed byte string holding the decimal form of n.
 bstr n_to_s(int n) {
-	word[24] b; int i = 0, j = 0, neg = 0; bstr p; char* t;
+	word[24] b = {}; int i = 0, j = 0, neg = 0; bstr p; char* t;
 	if (!n) { p = new_s(1); sput(p, 0, '0'); sput(p, 1, 0); return p; }
 	if (n < 0) { neg = 1; n = 0 - n; }
 	if (n < 0) {
@@ -431,7 +431,7 @@ const int F_HASDROP = 16, F_DROPPED = 32, F_FINAL = 64, F_CYCLE = 128;	// F_CYCL
 int o3_depth, gc_pending, gc_cyc;	// gc_cyc: the last sweep found a cycle with drops to run
 // flags live in these bits; the size class is above them.
 const int F_LOW = 65535;
-int hbump; word[32] freel; int gc_runs, gc_freed, gc_auto = 1;
+int hbump; word[32] freel = {}; int gc_runs, gc_freed, gc_auto = 1;
 // block walks and new chunks stop here.
 int hstop;
 // while nonzero, balloc will not return a block overlapping this range.
@@ -1201,7 +1201,7 @@ int line_of(word b, int a) {
 }
 // write the hexadecimal form of a number
 int put_hex(int n) {
-	char[20] b; int i = 0, d;
+	char[20] b = {}; int i = 0, d;
 	put_s("0x");
 	if (!n) { put_c('0'); return 0; }
 	while (n && i < 16) { d = n & 15; if (d < 10) b[i++] = '0' + d; else b[i++] = 'a' + d - 10; n = n >> 4; }