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[Macros] Don't expand macros inside macro expession arguments #65519

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Merged
merged 1 commit into from
May 1, 2023
Merged

[Macros] Don't expand macros inside macro expession arguments #65519

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10 changes: 9 additions & 1 deletion lib/Sema/CSApply.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5389,7 +5389,15 @@ namespace {
E->setMacroRef(macroRef);
E->setType(expandedType);

if (!cs.Options.contains(ConstraintSystemFlags::DisableMacroExpansions)) {
// FIXME: Expansion should be lazy.
// i.e. 'ExpandMacroExpansionExprRequest' should be sinked into
// 'getRewritten()', and performed on-demand.
if (!cs.Options.contains(ConstraintSystemFlags::DisableMacroExpansions) &&
// Do not expand macros inside macro arguments. For example for
// '#stringify(#assert(foo))' when typechecking `#assert(foo)`,
// we don't want to expand it.
llvm::none_of(makeArrayRef(ExprStack).drop_back(1),
[](Expr *E) { return isa<MacroExpansionExpr>(E); })) {
(void)evaluateOrDefault(cs.getASTContext().evaluator,
ExpandMacroExpansionExprRequest{E}, None);
}
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14 changes: 14 additions & 0 deletions test/Macros/macro_expand.swift
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Expand Up @@ -179,6 +179,20 @@ func testDiscardableStringify(x: Int) {
}
#endif

#if TEST_DIAGNOSTICS
// This causes an error when non-'Bool' value is passed.
@freestanding(expression) macro assertAny<T>(_ value: T) = #externalMacro(module: "MacroDefinition", type: "AssertMacro")

func testNested() {
struct Nested { }
_ = #stringify(#assertAny(Nested()))
// expected-note@-1 2 {{in expansion of macro 'stringify' here}}
// CHECK-DIAGS-NOT: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
// CHECK-DIAGS: @__swiftmacro_9MacroUser10testNestedyyF9stringifyfMf_9assertAnyfMf_.swift:1:8: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
// CHECK-DIAGS-NOT: error: cannot convert value of type 'Nested' to expected argument type 'Bool'
}
#endif

func testStringifyWithThrows() throws {
// Okay, we can put the try inside or outside
_ = try #stringify(maybeThrowing())
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