| 1 | // RUN: %clang_cc1 -fsyntax-only -verify -std=c++1y %s |
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| 2 | |
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| 3 | // expected-no-diagnostics |
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| 4 | |
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| 5 | // C++11 [basic.link]p6: |
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| 6 | // The name of a function declared in block scope and the name |
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| 7 | // of a variable declared by a block scope extern declaration |
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| 8 | // have linkage. If there is a visible declaration of an entity |
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| 9 | // with linkage having the same name and type, ignoring entities |
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| 10 | // declared outside the innermost enclosing namespace scope, the |
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| 11 | // block scope declaration declares that same entity and |
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| 12 | // receives the linkage of the previous declaration. |
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| 13 | |
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| 14 | extern int same_entity; |
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| 15 | constexpr int *get1() { |
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| 16 | int same_entity = 0; // not the same entity |
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| 17 | { |
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| 18 | extern int same_entity; |
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| 19 | return &same_entity; |
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| 20 | } |
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| 21 | } |
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| 22 | static_assert(get1() == &same_entity, "failed to find previous decl"); |
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| 23 | |
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| 24 | static int same_entity_2[3]; |
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| 25 | constexpr int *get2() { |
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| 26 | // This is a redeclaration of the same entity, even though it doesn't |
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| 27 | // inherit the type of the prior declaration. |
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| 28 | extern int same_entity_2[]; |
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| 29 | return same_entity_2; |
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| 30 | } |
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| 31 | static_assert(get2() == same_entity_2, "failed to find previous decl"); |
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| 32 | |
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| 33 | static int different_entities; |
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| 34 | constexpr int *get3() { |
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| 35 | int different_entities = 0; |
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| 36 | { |
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| 37 | // FIXME: This is not a redeclaration of the prior entity, because |
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| 38 | // it is not visible here. Under DR426, this is ill-formed, and without |
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| 39 | // it, the static_assert below should fail. |
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| 40 | extern int different_entities; |
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| 41 | return &different_entities; |
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| 42 | } |
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| 43 | } |
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| 44 | static_assert(get3() == &different_entities, "failed to find previous decl"); |
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| 45 | |
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