astgen: do not discard result location in for/while loops

If we use the discard result location any break with a value will be
ignored and not checked for usage.

Closes https://github.com/ziglang/zig/issues/14684.

2 files changed, 41 insertions, 0 deletions

diff --git a/test/cases/compile_errors/for_loop_break_value_ignored.zig b/test/cases/compile_errors/for_loop_break_value_ignored.zig
new file mode 100644
index 0000000000..a1119ec651
--- /dev/null
+++ b/test/cases/compile_errors/for_loop_break_value_ignored.zig
@@ -0,0 +1,15 @@
+fn returns() usize {
+    return 2;
+}
+
+export fn f1() void {
+    for ("hello") |_| {
+        break returns();
+    }
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :6:5: error: incompatible types: 'usize' and 'void'
diff --git a/test/cases/compile_errors/while_loop_break_value_ignored.zig b/test/cases/compile_errors/while_loop_break_value_ignored.zig
new file mode 100644
index 0000000000..2d14693fe5
--- /dev/null
+++ b/test/cases/compile_errors/while_loop_break_value_ignored.zig
@@ -0,0 +1,26 @@
+fn returns() usize {
+    return 2;
+}
+
+export fn f1() void {
+    var a: bool = true;
+    while (a) {
+        break returns();
+    }
+}
+
+export fn f2() void {
+    var x: bool = true;
+    outer: while (x) {
+        while (x) {
+            break :outer returns();
+        }
+    }
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :7:5: error: incompatible types: 'usize' and 'void'
+// :14:12: error: incompatible types: 'usize' and 'void'