[c++20] Implement P0428R2 - Familiar template syntax for generic lambdas
Differential Revision: https://reviews.llvm.org/D36527
llvm-svn: 359967
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index c3094d6..87a6b4d 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -638,6 +638,8 @@
///
/// lambda-expression:
/// lambda-introducer lambda-declarator[opt] compound-statement
+/// lambda-introducer '<' template-parameter-list '>'
+/// lambda-declarator[opt] compound-statement
///
/// lambda-introducer:
/// '[' lambda-capture[opt] ']'
@@ -1121,6 +1123,33 @@
<< A.getName()->getName();
};
+ // FIXME: Consider allowing this as an extension for GCC compatibiblity.
+ const bool HasExplicitTemplateParams = Tok.is(tok::less);
+ ParseScope TemplateParamScope(this, Scope::TemplateParamScope,
+ /*EnteredScope=*/HasExplicitTemplateParams);
+ if (HasExplicitTemplateParams) {
+ Diag(Tok, getLangOpts().CPlusPlus2a
+ ? diag::warn_cxx17_compat_lambda_template_parameter_list
+ : diag::ext_lambda_template_parameter_list);
+
+ SmallVector<NamedDecl*, 4> TemplateParams;
+ SourceLocation LAngleLoc, RAngleLoc;
+ if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(),
+ TemplateParams, LAngleLoc, RAngleLoc)) {
+ Actions.ActOnLambdaError(LambdaBeginLoc, getCurScope());
+ return ExprError();
+ }
+
+ if (TemplateParams.empty()) {
+ Diag(RAngleLoc,
+ diag::err_lambda_template_parameter_list_empty);
+ } else {
+ Actions.ActOnLambdaExplicitTemplateParameterList(
+ LAngleLoc, TemplateParams, RAngleLoc);
+ ++CurTemplateDepthTracker;
+ }
+ }
+
TypeResult TrailingReturnType;
if (Tok.is(tok::l_paren)) {
ParseScope PrototypeScope(this,
@@ -1137,13 +1166,20 @@
SourceLocation EllipsisLoc;
if (Tok.isNot(tok::r_paren)) {
- Actions.RecordParsingTemplateParameterDepth(TemplateParameterDepth);
+ Actions.RecordParsingTemplateParameterDepth(
+ CurTemplateDepthTracker.getOriginalDepth());
+
ParseParameterDeclarationClause(D, Attr, ParamInfo, EllipsisLoc);
+
// For a generic lambda, each 'auto' within the parameter declaration
// clause creates a template type parameter, so increment the depth.
+ // If we've parsed any explicit template parameters, then the depth will
+ // have already been incremented. So we make sure that at most a single
+ // depth level is added.
if (Actions.getCurGenericLambda())
- ++CurTemplateDepthTracker;
+ CurTemplateDepthTracker.setAddedDepth(1);
}
+
T.consumeClose();
SourceLocation RParenLoc = T.getCloseLocation();
SourceLocation DeclEndLoc = RParenLoc;
@@ -1298,6 +1334,7 @@
StmtResult Stmt(ParseCompoundStatementBody());
BodyScope.Exit();
+ TemplateParamScope.Exit();
if (!Stmt.isInvalid() && !TrailingReturnType.isInvalid())
return Actions.ActOnLambdaExpr(LambdaBeginLoc, Stmt.get(), getCurScope());