Improve error messages for break type coercion

src/Module.zig

@@ -5949,7 +5949,7 @@ pub const PeerTypeCandidateSrc = union(enum) {
     none: void,
     /// When we want to know the the src of candidate i, look up at
     /// index i in this slice
-    override: []LazySrcLoc,
+    override: []?LazySrcLoc,
     /// resolvePeerTypes originates from a @TypeOf(...) call
     typeof_builtin_call_node_offset: i32,