Commit Graph

11 Commits

Author SHA1 Message Date
Richard Smith 00e5d38d40 Do not warn that an expression of the form (void)arr; is unused when
arr is a volatile non-local array.

This fixes a recent regression exposed by removing lvalue-to-rvalue
conversion of discarded volatile arrays. In passing, regularize the
rules we use to determine whether '(void)expr;' warns when expr is a
volatile glvalue.
2020-05-27 17:26:29 -07:00
Daniel Jasper 9c81a727eb Look through CXXBindTemporaryExprs when checking CXXFunctionCastExprs
for unused values.

This fixes a regression caused by r298676, where constructor calls to
classes with non-trivial dtor were marked as unused if the first
argument is an initializer list. This is inconsistent (as the test
shows) and also warns on a reasonbly common code pattern where people
just call constructors to create and immediately destroy an object.

llvm-svn: 298853
2017-03-27 16:29:41 +00:00
Charles Li 1a88adbb27 Lit C++11 Compatibility Patch #8
24 tests have been updated for C++11 compatibility.

llvm-svn: 266387
2016-04-14 23:47:07 +00:00
Aaron Ballman 409af50858 Volatile reads are side-effecting operations, but in the general case of access through a volatile-qualified type, we're not certain of the underlying object's side-effects on access.
Treat volatile accesses as "maybe" instead of "definite" side effects for the purposes of warning on evaluations in an unevaluated context. No longer diagnose on idiomatic code like:

int * volatile v;
(void)sizeof(*v);

llvm-svn: 225116
2015-01-03 17:00:12 +00:00
Aaron Ballman 6c93b3e29c Adding a -Wunused-value warning for expressions with side effects used in an unevaluated expression context, such as sizeof(), or decltype(). Also adds a similar warning when the expression passed to typeid() *is* evaluated, since it is equally likely that the user would expect the expression operand to be unevaluated in that case.
llvm-svn: 224465
2014-12-17 21:57:17 +00:00
Benjamin Kramer 35e6fee3e9 Sema: Reject templates in all extern "C" contexts.
Otherwise we'd accept them if the LinkageDecl was not the direct
parent DeclContext. PR17968.

llvm-svn: 200641
2014-02-02 16:35:43 +00:00
Lubos Lunak 1f490f3aea report unused-value warning also for warn_unused types
llvm-svn: 186793
2013-07-21 13:15:58 +00:00
Eli Friedman c11535c248 Add a warning to diagnose statements in C++ like "*(volatile int*)x;". Conceptually, this is part of -Wunused-value, but I added a separate flag -Wunused-volatile-lvalue so it doesn't get turned off by accident with -Wno-unused-value. I also made a few minor improvements to existing unused value warnings in the process. <rdar://problem/11516811>.
llvm-svn: 157362
2012-05-24 00:47:05 +00:00
Nick Lewycky fcd5e7a160 When emitting a diagnostic about two-phase name lookup, don't do useless
qualified name lookups into transparent contexts.

llvm-svn: 152739
2012-03-14 20:41:00 +00:00
Matt Beaumont-Gay dcaacaa190 Fix a QoI bug with overloaded operators inside macros.
We were failing to set source locations and ranges in isUnusedResultAWarning
for CXXOperatorCallExprs, leading to an "expression result unused" warning
with absolutely no context if the expression was inside a macro.

llvm-svn: 140036
2011-09-19 18:51:20 +00:00
John McCall c493a73240 Improve the unused-value check to look into comma expressions and filter out
voids in sub-expressions.  Patch by Mike M!

Fixes PR4806.

llvm-svn: 98335
2010-03-12 07:11:26 +00:00