[clang] [clang-tools-extra] [Clang][AST] Introduce `ExplicitInstantiationDecl` to preserve source info and fix diagnostic locations (PR #191658)

[via cfe-commits]

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@@ -9314,10 +9314,40 @@ static void StripImplicitInstantiation(NamedDecl *D, bool MinGW) {
     FD->setInlineSpecified(false);
 }
 
+/// Create an ExplicitInstantiationDecl to record source-location info for an
+/// explicit template instantiation statement, and add it to \p CurContext.
+static void addExplicitInstantiationDecl(
+    ASTContext &Context, DeclContext *CurContext, const CXXScopeSpec &SS,
+    SourceLocation EndLoc, NamedDecl *Spec, SourceLocation ExternLoc,
+    SourceLocation TemplateLoc, SourceLocation TagKWLoc,
+    const ASTTemplateArgumentListInfo *ArgsAsWritten, SourceLocation NameLoc,
+    TypeSourceInfo *TypeAsWritten, TemplateSpecializationKind TSK) {
+  NestedNameSpecifierLoc QualifierLoc;
+  if (SS.isNotEmpty())
+    QualifierLoc = SS.getWithLocInContext(Context);
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16bit-ykiko wrote:

Fixed.

https://github.com/llvm/llvm-project/pull/191658