Sema: further enhance explanation of why expr is evaluated at comptime

1 files changed, 48 insertions, 0 deletions

diff --git a/test/cases/compile_errors/condition_comptime_reason_explained.zig b/test/cases/compile_errors/condition_comptime_reason_explained.zig
new file mode 100644
index 0000000000..332ae8afc8
--- /dev/null
+++ b/test/cases/compile_errors/condition_comptime_reason_explained.zig
@@ -0,0 +1,48 @@
+const S = struct {
+    fnPtr: fn () void,
+};
+fn bar() void {}
+fn baz() void {}
+var runtime: bool = true;
+fn ifExpr() S {
+    if (runtime) {
+        return .{
+            .fnPtr = bar,
+        };
+    } else {
+        return .{
+            .fnPtr = baz,
+        };
+    }
+}
+pub export fn entry1() void {
+    _ = ifExpr();
+}
+fn switchExpr() S {
+    switch (runtime) {
+        true => return .{
+            .fnPtr = bar,
+        },
+        false => return .{
+            .fnPtr = baz,
+        },
+    }
+}
+pub export fn entry2() void {
+    _ = switchExpr();
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :8:9: error: unable to resolve comptime value
+// :8:9: note: condition in comptime branch must be comptime-known
+// :7:13: note: expression is evaluated at comptime because the function returns a comptime-only type 'tmp.S'
+// :2:12: note: struct requires comptime because of this field
+// :2:12: note: use '*const fn() void' for a function pointer type
+// :19:15: note: called from here
+// :22:13: error: unable to resolve comptime value
+// :22:13: note: condition in comptime switch must be comptime-known
+// :21:17: note: expression is evaluated at comptime because the function returns a comptime-only type 'tmp.S'
+// :32:19: note: called from here