contextual void construction

compiler_tests.odin

@@ -2527,6 +2527,98 @@ main :: func() i32 {
 	testing.expect(t, found_incompatible)
 }
 
+@(test)
+match_call_subject_and_contextual_void_compile :: proc(t: ^testing.T) {
+	// Milestone 22.6: (1) a call expression directly as the match subject (`match get()`)
+	// now specializes — previously "could not resolve specialization of 'get'" — because the
+	// inference pass visits the match subject; (2) a void variant constructed contextually
+	// (`e Box = .empty`) coerces the bare enum literal to the union. Both compile clean to IR.
+	text := `Animal :: enum {
+	dog
+	cat
+	bird
+}
+Box :: union(enum) {
+	count i32
+	empty void
+}
+get :: func() Animal {
+	return .bird
+}
+main :: func() i32 {
+	e Box = .empty
+	r i32 = 0
+	match get() {
+		.dog:  r = 1
+		.cat:  r = 2
+		.bird: r = 3
+	}
+	match e {
+		.count |c|: r = r + c
+		.empty:     r = r + 7
+	}
+	return r
+}
+`
+	source_file := source.Source{path="test.bro", text=text}
+	diagnostics := source.init_diagnostics(&source_file)
+	defer source.destroy_diagnostics(&diagnostics)
+	symbols := symbol.init_table()
+	defer symbol.destroy_table(&symbols)
+	stream := lexer.lex(&source_file, &diagnostics, &symbols)
+	defer delete(stream.items)
+	ast_module := parser.parse(&stream, &source_file, &diagnostics)
+	defer ast.destroy_module(&ast_module)
+	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
+	defer hir.destroy_module(&hir_module)
+	ir_module := lower.lower(&hir_module)
+	defer ir.destroy_module(&ir_module)
+	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
+	defer delete(llvm_text)
+
+	testing.expect_value(t, len(diagnostics.items), 0)
+	testing.expect(t, strings.contains(llvm_text, "icmp eq")) // the call subject still dispatches
+}
+
+@(test)
+match_contextual_payload_variant_is_diagnosed :: proc(t: ^testing.T) {
+	// Contextual construction is only for void variants; a bare `.point` for a payload
+	// variant must use `Box{ point = ... }` instead.
+	text := `Point :: struct {
+	x i32
+	y i32
+}
+Box :: union(enum) {
+	point Point
+	empty void
+}
+bad :: func() i32 {
+	e Box = .point
+	return 0
+}
+main :: func() i32 {
+	return bad()
+}
+`
+	source_file := source.Source{path="test.bro", text=text}
+	diagnostics := source.init_diagnostics(&source_file)
+	defer source.destroy_diagnostics(&diagnostics)
+	symbols := symbol.init_table()
+	defer symbol.destroy_table(&symbols)
+	stream := lexer.lex(&source_file, &diagnostics, &symbols)
+	defer delete(stream.items)
+	ast_module := parser.parse(&stream, &source_file, &diagnostics)
+	defer ast.destroy_module(&ast_module)
+	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
+	defer hir.destroy_module(&hir_module)
+
+	found := false
+	for diagnostic in diagnostics.items {
+		found = found || strings.contains(diagnostic.message, "needs a payload")
+	}
+	testing.expect(t, found)
+}
+
 @(test)
 yield_misuse_is_diagnosed :: proc(t: ^testing.T) {
 	// A value block that does not end in `yield`, and a `yield` nested inside an