e57a9abc4b
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after incorrect check in NonTypeTemplateParmDecl broke lldb.
Differential Revision: https://reviews.llvm.org/D65042
20 lines
1.0 KiB
C++
20 lines
1.0 KiB
C++
// RUN: %clang_cc1 -std=c++2a -fconcepts-ts -verify %s
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auto l1 = [] (auto x) requires (sizeof(decltype(x)) == 1) { return x; };
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// expected-note@-1{{candidate template ignored: constraints not satisfied [with x:auto = int]}}
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// expected-note@-2{{because 'sizeof(decltype(x)) == 1' (4 == 1) evaluated to false}}
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auto l1t1 = l1('a');
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auto l1t2 = l1(1);
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// expected-error@-1{{no matching function for call to object of type '(lambda at}}
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auto l2 = [] (auto... x) requires ((sizeof(decltype(x)) >= 2) && ...) { return (x + ...); };
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// expected-note@-1{{candidate template ignored: constraints not satisfied [with x:auto = <char>]}}
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// expected-note@-2{{candidate template ignored: constraints not satisfied [with x:auto = <int, char>]}}
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// expected-note@-3 2{{because 'sizeof(decltype(x)) >= 2' (1 >= 2) evaluated to false}}
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auto l2t1 = l2('a');
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// expected-error@-1{{no matching function for call to object of type '(lambda at}}
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auto l2t2 = l2(1, 'a');
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// expected-error@-1{{no matching function for call to object of type '(lambda at}}
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auto l2t3 = l2((short)1, (short)1); |