Merge pull request #15880 from mlugg/feat/better-switch-zir-2

Simplify and compact switch ZIR, and resolve union payload captures with PTR

4 files changed, 97 insertions, 23 deletions

diff --git a/test/behavior/switch.zig b/test/behavior/switch.zig
index 3f6cd37298..72a36c9883 100644
--- a/test/behavior/switch.zig
+++ b/test/behavior/switch.zig
@@ -1,5 +1,6 @@
 const builtin = @import("builtin");
 const std = @import("std");
+const assert = std.debug.assert;
 const expect = std.testing.expect;
 const expectError = std.testing.expectError;
 const expectEqual = std.testing.expectEqual;
@@ -717,3 +718,70 @@ test "comptime inline switch" {
 
     try expectEqual(u32, value);
 }
+
+test "switch capture peer type resolution" {
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+
+    const U = union(enum) {
+        a: u32,
+        b: u64,
+        fn innerVal(u: @This()) u64 {
+            switch (u) {
+                .a, .b => |x| return x,
+            }
+        }
+    };
+
+    try expectEqual(@as(u64, 100), U.innerVal(.{ .a = 100 }));
+    try expectEqual(@as(u64, 200), U.innerVal(.{ .b = 200 }));
+}
+
+test "switch capture peer type resolution for in-memory coercible payloads" {
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+
+    const T1 = c_int;
+    const T2 = @Type(@typeInfo(T1));
+
+    comptime assert(T1 != T2);
+
+    const U = union(enum) {
+        a: T1,
+        b: T2,
+        fn innerVal(u: @This()) c_int {
+            switch (u) {
+                .a, .b => |x| return x,
+            }
+        }
+    };
+
+    try expectEqual(@as(c_int, 100), U.innerVal(.{ .a = 100 }));
+    try expectEqual(@as(c_int, 200), U.innerVal(.{ .b = 200 }));
+}
+
+test "switch pointer capture peer type resolution" {
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+
+    const T1 = c_int;
+    const T2 = @Type(@typeInfo(T1));
+
+    comptime assert(T1 != T2);
+
+    const U = union(enum) {
+        a: T1,
+        b: T2,
+        fn innerVal(u: *@This()) *c_int {
+            switch (u.*) {
+                .a, .b => |*ptr| return ptr,
+            }
+        }
+    };
+
+    var ua: U = .{ .a = 100 };
+    var ub: U = .{ .b = 200 };
+
+    ua.innerVal().* = 111;
+    ub.innerVal().* = 222;
+
+    try expectEqual(U{ .a = 111 }, ua);
+    try expectEqual(U{ .b = 222 }, ub);
+}
diff --git a/test/cases/compile_errors/capture_group_on_switch_prong_with_incompatible_payload_types.zig b/test/cases/compile_errors/capture_group_on_switch_prong_with_incompatible_payload_types.zig
deleted file mode 100644
index cff9a58bc6..0000000000
--- a/test/cases/compile_errors/capture_group_on_switch_prong_with_incompatible_payload_types.zig
+++ /dev/null
@@ -1,21 +0,0 @@
-const Union = union(enum) {
-    A: usize,
-    B: isize,
-};
-comptime {
-    var u = Union{ .A = 8 };
-    switch (u) {
-        .A, .B => |e| {
-            _ = e;
-            unreachable;
-        },
-    }
-}
-
-// error
-// backend=stage2
-// target=native
-//
-// :8:20: error: capture group with incompatible types
-// :8:10: note: type 'usize' here
-// :8:14: note: type 'isize' here
diff --git a/test/cases/compile_errors/switch_capture_incompatible_types.zig b/test/cases/compile_errors/switch_capture_incompatible_types.zig
new file mode 100644
index 0000000000..b6de7d5bf5
--- /dev/null
+++ b/test/cases/compile_errors/switch_capture_incompatible_types.zig
@@ -0,0 +1,27 @@
+export fn f() void {
+    const U = union(enum) { a: u32, b: *u8 };
+    var u: U = undefined;
+    switch (u) {
+        .a, .b => |val| _ = val,
+    }
+}
+
+export fn g() void {
+    const U = union(enum) { a: u64, b: u32 };
+    var u: U = undefined;
+    switch (u) {
+        .a, .b => |*ptr| _ = ptr,
+    }
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :5:20: error: capture group with incompatible types
+// :5:20: note: incompatible types: 'u32' and '*u8'
+// :5:10: note: type 'u32' here
+// :5:14: note: type '*u8' here
+// :13:20: error: capture group with incompatible types
+// :13:14: note: pointer type child 'u32' cannot cast into resolved pointer type child 'u64'
+// :13:20: note: this coercion is only possible when capturing by value
diff --git a/test/cases/compile_errors/switch_on_union_with_no_attached_enum.zig b/test/cases/compile_errors/switch_on_union_with_no_attached_enum.zig
index 4d8742d32e..d9bc2abb91 100644
--- a/test/cases/compile_errors/switch_on_union_with_no_attached_enum.zig
+++ b/test/cases/compile_errors/switch_on_union_with_no_attached_enum.zig
@@ -4,12 +4,12 @@ const Payload = union {
     C: bool,
 };
 export fn entry() void {
-    const a = Payload { .A = 1234 };
+    const a = Payload{ .A = 1234 };
     foo(&a);
 }
 fn foo(a: *const Payload) void {
     switch (a.*) {
-        Payload.A => {},
+        .A => {},
         else => unreachable,
     }
 }