Author: Haojian Wu Date: 2020-11-30T09:19:15+01:00 New Revision: ec6c5e920a89db0e1c5f73b8349ee0b84192072d
URL: https://github.com/llvm/llvm-project/commit/ec6c5e920a89db0e1c5f73b8349ee0b84192072d DIFF: https://github.com/llvm/llvm-project/commit/ec6c5e920a89db0e1c5f73b8349ee0b84192072d.diff LOG: [clang] Improve diagnostics for auto-return-type function if the return expr had an error. Given the following case: ``` auto k() { return undef(); return 1; } ``` Prior to the patch, clang emits an `cannot initialize return object of type 'auto' with an rvalue of type 'int'` diagnostic on the second return (because the return type of the function cannot be deduced from the first contain-errors return). This patch suppresses this error. Differential Revision: https://reviews.llvm.org/D92211 Added: Modified: clang/lib/Sema/SemaStmt.cpp clang/test/SemaCXX/attr-target-mv.cpp clang/test/SemaCXX/cxx1y-deduced-return-type.cpp clang/test/SemaCXX/lambda-expressions.cpp Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp index 195121e1e256..f5bf889b3878 100644 --- a/clang/lib/Sema/SemaStmt.cpp +++ b/clang/lib/Sema/SemaStmt.cpp @@ -3327,9 +3327,14 @@ Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { } if (HasDeducedReturnType) { + FunctionDecl *FD = CurLambda->CallOperator; + // If we've already decided this lambda is invalid, e.g. because + // we saw a `return` whose expression had an error, don't keep + // trying to deduce its return type. + if (FD->isInvalidDecl()) + return StmtError(); // In C++1y, the return type may involve 'auto'. // FIXME: Blocks might have a return type of 'auto' explicitly specified. - FunctionDecl *FD = CurLambda->CallOperator; if (CurCap->ReturnType.isNull()) CurCap->ReturnType = FD->getReturnType(); @@ -3709,6 +3714,11 @@ StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { if (getLangOpts().CPlusPlus14) { if (AutoType *AT = FnRetType->getContainedAutoType()) { FunctionDecl *FD = cast<FunctionDecl>(CurContext); + // If we've already decided this function is invalid, e.g. because + // we saw a `return` whose expression had an error, don't keep + // trying to deduce its return type. + if (FD->isInvalidDecl()) + return StmtError(); if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) { FD->setInvalidDecl(); return StmtError(); diff --git a/clang/test/SemaCXX/attr-target-mv.cpp b/clang/test/SemaCXX/attr-target-mv.cpp index 11f3a276c7c7..5ef1d398d2d8 100644 --- a/clang/test/SemaCXX/attr-target-mv.cpp +++ b/clang/test/SemaCXX/attr-target-mv.cpp @@ -107,7 +107,6 @@ int __attribute__((target("arch=sandybridge"))) diff _mangle(void) { return 0; } // expected-error@+1 {{multiversioned functions do not yet support deduced return types}} auto __attribute__((target("default"))) deduced_return(void) { return 0; } -// expected-error@-1 {{cannot initialize return object of type 'auto' with an rvalue of type 'int'}} auto __attribute__((target("default"))) trailing_return(void)-> int { return 0; } diff --git a/clang/test/SemaCXX/cxx1y-deduced-return-type.cpp b/clang/test/SemaCXX/cxx1y-deduced-return-type.cpp index 958728b10487..3e544c300884 100644 --- a/clang/test/SemaCXX/cxx1y-deduced-return-type.cpp +++ b/clang/test/SemaCXX/cxx1y-deduced-return-type.cpp @@ -22,7 +22,7 @@ int conv1d = conv1.operator int(); // expected-error {{no member named 'operator struct Conv2 { operator auto() { return 0; } // expected-note {{previous}} - operator auto() { return 0.; } // expected-error {{cannot be redeclared}} expected-error {{cannot initialize return object of type 'auto' with an rvalue of type 'double'}} + operator auto() { return 0.; } // expected-error {{cannot be redeclared}} }; struct Conv3 { @@ -100,7 +100,7 @@ auto fac(int n) { auto fac_2(int n) { // expected-note {{declared here}} if (n > 2) return n * fac_2(n-1); // expected-error {{cannot be used before it is defined}} - return n; // expected-error {{cannot initialize return object of type 'auto'}} + return n; } auto void_ret() {} @@ -617,7 +617,6 @@ namespace PR33222 { }; template<> auto *B<char[1]>::q() { return (int*)0; } template<> auto B<char[2]>::q() { return (int*)0; } // expected-error {{return type}} - // FIXME: suppress this follow-on error: expected-error@-1 {{cannot initialize}} template<> int B<char[3]>::q() { return 0; } // expected-error {{return type}} } diff --git a/clang/test/SemaCXX/lambda-expressions.cpp b/clang/test/SemaCXX/lambda-expressions.cpp index 7f7f9c570487..22e0939379f5 100644 --- a/clang/test/SemaCXX/lambda-expressions.cpp +++ b/clang/test/SemaCXX/lambda-expressions.cpp @@ -521,6 +521,10 @@ void foo() { return undeclared_error; // expected-error {{use of undeclared identifier}} return 0; }; + auto bar = []() { + return undef(); // expected-error {{use of undeclared identifier}} + return 0; // verify no init_conversion_failed diagnostic emitted. + }; } } _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
