[clangd] Improve type printing in hover

[kadircet]

Summary

Do not include tag keywords when printing types for symbol names, as it
will come from SymbolKind.
Also suppress them while printing definitions to prevent them occuring in
template arguments.
Make use of getAsString, instead of print in all places to have a consistent
style across the file.

[merge_guards_bot]

Unit tests: pass. 61327 tests passed, 0 failed and 738 were skipped.

clang-tidy: pass.

clang-format: pass.

Build artifacts: diff.json, clang-tidy.txt, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

[sammccall]

Nice!

clang-tools-extra/clangd/Hover.cpp

 #include "AST.h"
 #include "CodeCompletionStrings.h"
 #include "FindTarget.h"
 #include "FormattedString.h"
 #include "Logger.h"
 #include "Selection.h"
 #include "SourceCode.h"
 #include "index/SymbolCollector.h"
-
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTTypeTraits.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/PrettyPrinter.h"
+#include "clang/AST/Type.h"
 #include "clang/Index/IndexSymbol.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/raw_ostream.h"
 #include <string>
 

 
 std::string printDefinition(const Decl *D) {
   std::string Definition;
   llvm::raw_string_ostream OS(Definition);
   PrintingPolicy Policy =
       printingPolicyForDecls(D->getASTContext().getPrintingPolicy());
   Policy.IncludeTagDefinition = false;
   Policy.SuppressTemplateArgsInCXXConstructors = true;
+  Policy.SuppressTagKeyword = true;
   D->print(OS, Policy);
   OS.flush();
   return Definition;
 }
 
 void printParams(llvm::raw_ostream &OS,
                  const std::vector<HoverInfo::Param> &Params) {
   for (size_t I = 0, E = Params.size(); I != E; ++I) {

 void fillFunctionTypeAndParams(HoverInfo &HI, const Decl *D,
                                const FunctionDecl *FD,
                                const PrintingPolicy &Policy) {
   HI.Parameters.emplace();
   for (const ParmVarDecl *PVD : FD->parameters()) {
     HI.Parameters->emplace_back();
     auto &P = HI.Parameters->back();
     if (!PVD->getType().isNull()) {
-      P.Type.emplace();
-      llvm::raw_string_ostream OS(*P.Type);
-      PVD->getType().print(OS, Policy);
+      P.Type = PVD->getType().getAsString(Policy);
     } else {
       std::string Param;
       llvm::raw_string_ostream OS(Param);
       PVD->dump(OS);
       OS.flush();
       elog("Got param with null type: {0}", Param);
     }
     if (!PVD->getName().empty())
if (const TemplateDecl *TD = D->getDescribedTemplate()) {
     if (const auto FTD = FD->getDescribedTemplate()) {
       HI.TemplateParameters =
           fetchTemplateParameters(FTD->getTemplateParameters(), Policy);
       D = FTD;
     }
   }
 
   // Fill in types and params.
-  if (const FunctionDecl *FD = getUnderlyingFunction(D)) {
+  if (const FunctionDecl *FD = getUnderlyingFunction(D))
     fillFunctionTypeAndParams(HI, D, FD, Policy);
-  } else if (const auto *VD = dyn_cast<ValueDecl>(D)) {
-    HI.Type.emplace();
-    llvm::raw_string_ostream OS(*HI.Type);
-    VD->getType().print(OS, Policy);
-  }
+  else if (const auto *VD = dyn_cast<ValueDecl>(D))
+    HI.Type = VD->getType().getAsString(Policy);
 
   // Fill in value with evaluated initializer if possible.
   if (const auto *Var = dyn_cast<VarDecl>(D)) {
     if (const Expr *Init = Var->getInit())
       HI.Value = printExprValue(Init, Ctx);
   } else if (const auto *ECD = dyn_cast<EnumConstantDecl>(D)) {
     // Dependent enums (e.g. nested in template classes) don't have values yet.
     if (!ECD->getType()->isDependentType())
if (const auto *D = T->getAsTagDecl()) {
     HI.Name = printName(ASTCtx, *D);
     HI.Kind = index::getSymbolInfo(D).Kind;
 
     const auto *CommentD = getDeclForComment(D);
     HI.Documentation = getDeclComment(ASTCtx, *CommentD);
     enhanceFromIndex(HI, *CommentD, Index);
   } else {
     // Builtin types
-    llvm::raw_string_ostream OS(HI.Name);
-    PrintingPolicy Policy = printingPolicyForDecls(ASTCtx.getPrintingPolicy());
-    T.print(OS, Policy);
+    auto Policy = printingPolicyForDecls(ASTCtx.getPrintingPolicy());
+    Policy.SuppressTagKeyword = true;
+    HI.Name = T.getAsString(Policy);
   }
   return HI;
 }
 
 /// Generate a \p Hover object given the macro \p MacroDecl.
 HoverInfo getHoverContents(const DefinedMacro &Macro, ParsedAST &AST) {
   HoverInfo HI;
   SourceManager &SM = AST.getSourceManager();

clang-tools-extra/clangd/unittests/HoverTests.cpp

class Foo {})cpp";
       {R"cpp(
         enum Color { RED, GREEN, };
         Color x = GREEN;
         Color y = [[^x]];
        )cpp",
        [](HoverInfo &HI) {
          HI.Name = "x";
          HI.NamespaceScope = "";
-         HI.Definition = "enum Color x = GREEN";
+         HI.Definition = "Color x = GREEN";
          HI.Kind = index::SymbolKind::Variable;
          HI.Type = "enum Color";
          HI.Value = "GREEN (1)"; // Symbolic when hovering on an expression.
        }},
       {R"cpp(
         template<int a, int b> struct Add {
           static constexpr int result = a + b;
         };
const std::function<void(HoverInfo &)> ExpectedBuilder;
             void test() { Test && [[te^st]] = {}; }
           )cpp",
           [](HoverInfo &HI) {
             HI.Name = "test";
             HI.Kind = index::SymbolKind::Variable;
             HI.NamespaceScope = "";
             HI.LocalScope = "test::";
             HI.Type = "struct Test &&";
-            HI.Definition = "struct Test &&test = {}";
+            HI.Definition = "Test &&test = {}";
             HI.Value = "{}";
           }},
       {
           R"cpp(// auto on alias
           typedef int int_type;
           ^[[auto]] x = int_type();
           )cpp",
           [](HoverInfo &HI) { HI.Name = "int"; }},
const std::function<void(HoverInfo &)> ExpectedBuilder;
             HI.Kind = index::SymbolKind::InstanceMethod;
             HI.NamespaceScope = "";
             HI.LocalScope = "cls<int>::";
             HI.Name = "method";
             HI.Parameters.emplace();
             HI.ReturnType = "int";
             HI.Type = "int ()";
           }},
+      {
+          R"cpp(// type of nested templates.
+          template <class T> struct cls {};
+          cls<cls<cls<int>>> [[fo^o]];
+          )cpp",
+          [](HoverInfo &HI) {
+            HI.Definition = "cls<cls<cls<int>>> foo";
+            HI.Kind = index::SymbolKind::Variable;
+            HI.NamespaceScope = "";
+            HI.Name = "foo";
+            HI.Type = "cls<cls<cls<int> > >";
+            HI.Value = "{}";
+          }},
+      {
+          R"cpp(// type of nested templates.
+          template <class T> struct cls {};
+          [[cl^s]]<cls<cls<int>>> foo;
+          )cpp",
+          [](HoverInfo &HI) {
+            HI.Definition = "template <> struct cls<cls<cls<int>>> {}";
+            HI.Kind = index::SymbolKind::Struct;
+            HI.NamespaceScope = "";
+            HI.Name = "cls<cls<cls<int> > >";
+            HI.Documentation = "type of nested templates.";
+          }},
   };
 
   // Create a tiny index, so tests above can verify documentation is fetched.
   Symbol IndexSym = func("indexSymbol");
   IndexSym.Documentation = "comment from index";
   SymbolSlab::Builder Symbols;
   Symbols.insert(IndexSym);
   auto Index =