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[Index] Index generic parameters used inside extensions
Extensions redeclare all generic parameters of their extended type to add their additional restrictions. There are two issues with this model for indexing: - The generic paramter declarations of the extension are implicit so we wouldn't report them in the index. Any usage of the generic param in the extension references this implicit declaration so we don't include it in the index either. - The implicit re-declarations have their own USRs so any usage of a generic parameter inside an extension would use a different USR than declaration of the param in the extended type. To fix these issues, we replace the reference to the implicit generic parameter defined in the extension by a reference to the generic paramter defined in the extended type.
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‎lib/Index/Index.cpp

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#include "swift/AST/Comment.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/Expr.h"
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#include "swift/AST/GenericParamList.h"
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#include "swift/AST/Module.h"
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#include "swift/AST/ParameterList.h"
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#include "swift/AST/ProtocolConformance.h"
@@ -439,6 +440,57 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
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return true;
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}
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/// Extensions redeclare all generic parameters of their extended type to add
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/// their additional restrictions. There are two issues with this model for
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/// indexing:
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/// - The generic paramter declarations of the extension are implicit so we
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/// wouldn't report them in the index. Any usage of the generic param in
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/// the extension references this implicit declaration so we don't include
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/// it in the index either.
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/// - The implicit re-declarations have their own USRs so any usage of a
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/// generic parameter inside an extension would use a different USR than
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/// declaration of the param in the extended type.
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///
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/// To fix these issues, we replace the reference to the implicit generic
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/// parameter defined in the extension by a reference to the generic paramter
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/// defined in the extended type.
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///
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/// \returns the canonicalized replaced generic param decl if it can be found
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/// or \p GenParam otherwise.
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ValueDecl *
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canonicalizeGenericTypeParamDeclForIndex(GenericTypeParamDecl *GenParam) {
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auto Extension = dyn_cast_or_null<ExtensionDecl>(
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GenParam->getDeclContext()->getAsDecl());
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if (!Extension) {
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// We are not referencing a generic paramter defined in an extension.
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// Nothing to do.
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return GenParam;
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}
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assert(GenParam->isImplicit() &&
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"Generic param decls in extension should always be implicit and "
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"shadow a generic param in the extended type.");
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assert(Extension->getExtendedNominal() &&
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"The implict generic types on the extension should only be created "
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"if the extended type was found");
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auto ExtendedTypeGenSig =
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Extension->getExtendedNominal()->getGenericSignature();
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assert(ExtendedTypeGenSig && "Extension is generic but extended type not?");
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// The generic parameter in the extension has the same depths and index
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// as the one in the extended type.
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for (auto ExtendedTypeGenParam : ExtendedTypeGenSig->getGenericParams()) {
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if (ExtendedTypeGenParam->getIndex() == GenParam->getIndex() &&
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ExtendedTypeGenParam->getDepth() == GenParam->getDepth()) {
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assert(ExtendedTypeGenParam->getDecl() &&
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"The generic parameter defined on the extended type cannot be "
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"implicit.");
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return ExtendedTypeGenParam->getDecl();
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}
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}
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llvm_unreachable("Can't find the generic parameter in the extended type");
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}
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bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
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TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef, Type T,
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ReferenceMetaData Data) override {
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if (CtorTyRef)
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if (!reportRef(CtorTyRef, Loc, Info, Data.AccKind))
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return false;
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if (auto *GenParam = dyn_cast<GenericTypeParamDecl>(D)) {
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D = canonicalizeGenericTypeParamDeclForIndex(GenParam);
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}
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if (!reportRef(D, Loc, Info, Data.AccKind))
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return false;
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‎test/Index/index_generic_params.swift

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// RUN: %target-swift-ide-test -print-indexed-symbols -source-filename %s | %FileCheck %s
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// CHECK: [[@LINE+1]]:10 | protocol/Swift | P1 | s:14swift_ide_test2P1P | Def |
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protocol P1 {
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// CHECK: [[@LINE+1]]:18 | type-alias/associated-type/Swift | Assoc | s:14swift_ide_test2P1P5AssocQa | Def,RelChild |
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associatedtype Assoc
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}
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// CHECK: [[@LINE+1]]:10 | protocol/Swift | P2 | s:14swift_ide_test2P2P | Def |
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protocol P2 {}
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// MARK: - Test extening a simple generic type
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// CHECK: [[@LINE+4]]:7 | class/Swift | Foo | s:14swift_ide_test3FooC | Def |
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// CHECK: [[@LINE+3]]:11 | type-alias/generic-type-param/Swift | OtherParam | s:14swift_ide_test3FooC10OtherParamxmfp | Def,RelChild |
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// CHECK: [[@LINE+2]]:23 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test3FooC3Barq_mfp | Def,RelChild |
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// CHECK: [[@LINE+1]]:28 | protocol/Swift | P1 | s:14swift_ide_test2P1P | Ref |
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class Foo<OtherParam, Bar: P1> {}
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// CHECK: [[@LINE+4]]:11 | extension/ext-class/Swift | Foo | s:e:s:14swift_ide_test3FooCA2A2P2R_rlE3foo1xyq__tF | Def |
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// CHECK: [[@LINE+3]]:11 | class/Swift | Foo | s:14swift_ide_test3FooC | Ref,RelExt |
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// CHECK: [[@LINE+2]]:21 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test3FooC3Barq_mfp | Ref |
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// CHECK: [[@LINE+1]]:26 | protocol/Swift | P2 | s:14swift_ide_test2P2P | Ref |
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extension Foo where Bar: P2 {
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// CHECK: [[@LINE+1]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test3FooC3Barq_mfp | Ref,RelCont |
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func foo(x: Bar) {}
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// CHECK: [[@LINE+2]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test3FooC3Barq_mfp | Ref,RelCont |
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// CHECK: [[@LINE+1]]:19 | type-alias/associated-type/Swift | Assoc | s:14swift_ide_test2P1P5AssocQa | Ref,RelCont |
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func bar(x: Bar.Assoc) {}
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}
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// MARK: - Test extending a generic type in a generic context
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// CHECK: [[@LINE+1]]:15 | type-alias/generic-type-param/Swift | WrapperParam | s:14swift_ide_test7WrapperC0D5Paramxmfp | Def,RelChild |
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class Wrapper<WrapperParam> {
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// CHECK: [[@LINE+2]]:9 | class/Swift | Wrapped | s:14swift_ide_test7WrapperC7WrappedC | Def,RelChild |
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// CHECK: [[@LINE+1]]:29 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Def,RelChild |
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class Wrapped<OtherParam, Bar: P1> {}
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}
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// MARK: Extension restricted on param of inner type
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// CHECK: [[@LINE+1]]:33 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Ref |
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extension Wrapper.Wrapped where Bar: P2 {
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// CHECK: [[@LINE+1]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Ref,RelCont |
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func foo(x: Bar) {}
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// CHECK: [[@LINE+2]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Ref,RelCont |
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// CHECK: [[@LINE+1]]:19 | type-alias/associated-type/Swift | Assoc | s:14swift_ide_test2P1P5AssocQa | Ref,RelCont |
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func bar(x: Bar.Assoc) {}
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}
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// MARK: Extension restricted on generic param of outer type
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// CHECK: [[@LINE+1]]:33 | type-alias/generic-type-param/Swift | WrapperParam | s:14swift_ide_test7WrapperC0D5Paramxmfp | Ref |
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extension Wrapper.Wrapped where WrapperParam: P2 {
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// CHECK: [[@LINE+1]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Ref,RelCont |
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func foo(x: Bar) {}
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// CHECK: [[@LINE+2]]:15 | type-alias/generic-type-param/Swift | Bar | s:14swift_ide_test7WrapperC7WrappedC3Barqd_0_mfp | Ref,RelCont |
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// CHECK: [[@LINE+1]]:19 | type-alias/associated-type/Swift | Assoc | s:14swift_ide_test2P1P5AssocQa | Ref,RelCont |
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func bar(x: Bar.Assoc) {}
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}
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// MARK: - Test extening a non-generic type in a generic context
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// CHECK: [[@LINE+1]]:16 | type-alias/generic-type-param/Swift | Wrapper2Param | s:14swift_ide_test8Wrapper2C0D5Paramxmfp | Def,RelChild |
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class Wrapper2<Wrapper2Param> {
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class NonGenericWrapped {}
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}
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// CHECK: [[@LINE+1]]:44 | type-alias/generic-type-param/Swift | Wrapper2Param | s:14swift_ide_test8Wrapper2C0D5Paramxmfp | Ref |
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extension Wrapper2.NonGenericWrapped where Wrapper2Param: P1 {
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// CHECK: [[@LINE+1]]:15 | type-alias/generic-type-param/Swift | Wrapper2Param | s:14swift_ide_test8Wrapper2C0D5Paramxmfp | Ref,RelCont |
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func foo(x: Wrapper2Param) {}
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// CHECK: [[@LINE+2]]:15 | type-alias/generic-type-param/Swift | Wrapper2Param | s:14swift_ide_test8Wrapper2C0D5Paramxmfp | Ref,RelCont |
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// CHECK: [[@LINE+1]]:29 | type-alias/associated-type/Swift | Assoc | s:14swift_ide_test2P1P5AssocQa | Ref,RelCont |
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func bar(x: Wrapper2Param.Assoc) {}
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}
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// MARK: - Test extending an unkown type
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// Check that we don't crash. We don't expect the generic params to show up in the index.
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extension MyUnknownType where Wrapper2Param: P1 {
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func foo(x: Wrapper2Param) {}
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}

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