SemaTemplateInstantiate.cpp: warning: suggest parentheses around ‘&&’ within ‘||’

[aabhinavg1]

Warning: Suggest parentheses around '&&' within '||' in SemaTemplateInstantiate.cpp

Summary

While building Clang as part of the LLVM project, a compiler warning appears in
clang/lib/Sema/SemaTemplateInstantiate.cpp suggesting parentheses around && within ||.

/home/aitr/llvm/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2866:49: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
 2866 |     assert(!Success || !Trap.hasErrorOccurred() &&
      |                        ~~~~~~~~~~~~~~~~~~~~~~~~~^~
 2867 |                            "Substitution failures must be handled "
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2868 |                            "by CheckConstraintSatisfaction.");
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Steps to Reproduce

1. Clone the LLVM project:

   git clone https://github.com/llvm/llvm-project.git
   cd llvm-project
   mkdir build && cd build

2. Configure the build using CMake:

   cmake -G Ninja ../llvm  \
     -DLLVM_ENABLE_PROJECTS="clang;lld" \
     -DLLVM_USE_LINKER=lld \
     -DLLVM_PARALLEL_LINK_JOBS=1 \
     -DCMAKE_BUILD_TYPE=Debug \
     -DLLVM_ENABLE_ASSERTIONS=ON \
     -DLLVM_TARGETS_TO_BUILD="AMDGPU;PowerPC;AArch64;X86" \
     -DLLVM_ENABLE_DUMP=ON

3. Build Clang:

   ninja clang

4. Observe the warning during compilation of:

   clang/lib/Sema/SemaTemplateInstantiate.cpp
   

Analysis

The expression triggering the warning is:

assert(!Success || !Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction.");

Operator precedence causes && to bind tighter than ||, which may lead to ambiguous intent. Although semantically correct, adding parentheses improves clarity and suppresses warnings.

Proposed Fix

Wrap the && clause with parentheses for clarity:

assert(!Success || (!Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction."));

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor is working on this issue. If someone is assigned to the issue or claimed to be working on it, ping the person. After one week without a response, the assignee may be changed.
2. Leave a comment indicating that you are working on the issue, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: None (aabhinavg1)

# Warning: Suggest parentheses around '&&' within '||' in SemaTemplateInstantiate.cpp

Summary

While building Clang as part of the LLVM project, a compiler warning appears in
clang/lib/Sema/SemaTemplateInstantiate.cpp suggesting parentheses around && within ||.

/home/aitr/llvm/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2866:49: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
 2866 |     assert(!Success || !Trap.hasErrorOccurred() &&
      |                        ~~~~~~~~~~~~~~~~~~~~~~~~~^~
 2867 |                            "Substitution failures must be handled "
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2868 |                            "by CheckConstraintSatisfaction.");
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Steps to Reproduce

1. Clone the LLVM project:

   git clone https://github.com/llvm/llvm-project.git
   cd llvm-project
   mkdir build && cd build

2. Configure the build using CMake:

   cmake -G Ninja ../llvm  \
     -DLLVM_ENABLE_PROJECTS="clang;lld" \
     -DLLVM_USE_LINKER=lld \
     -DLLVM_PARALLEL_LINK_JOBS=1 \
     -DCMAKE_BUILD_TYPE=Debug \
     -DLLVM_ENABLE_ASSERTIONS=ON \
     -DLLVM_TARGETS_TO_BUILD="AMDGPU;PowerPC;AArch64;X86" \
     -DLLVM_ENABLE_DUMP=ON

3. Build Clang:

   ninja clang

4. Observe the warning during compilation of:

   clang/lib/Sema/SemaTemplateInstantiate.cpp
   

Analysis

The expression triggering the warning is:

assert(!Success || !Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction.");

Operator precedence causes && to bind tighter than ||, which may lead to ambiguous intent. Although semantically correct, adding parentheses improves clarity and suppresses warnings.

Proposed Fix

Wrap the && clause with parentheses for clarity:

assert(!Success || (!Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction."));

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (aabhinavg1)

# Warning: Suggest parentheses around '&&' within '||' in SemaTemplateInstantiate.cpp

Summary

While building Clang as part of the LLVM project, a compiler warning appears in
clang/lib/Sema/SemaTemplateInstantiate.cpp suggesting parentheses around && within ||.

/home/aitr/llvm/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2866:49: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
 2866 |     assert(!Success || !Trap.hasErrorOccurred() &&
      |                        ~~~~~~~~~~~~~~~~~~~~~~~~~^~
 2867 |                            "Substitution failures must be handled "
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2868 |                            "by CheckConstraintSatisfaction.");
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Steps to Reproduce

1. Clone the LLVM project:

   git clone https://github.com/llvm/llvm-project.git
   cd llvm-project
   mkdir build && cd build

2. Configure the build using CMake:

   cmake -G Ninja ../llvm  \
     -DLLVM_ENABLE_PROJECTS="clang;lld" \
     -DLLVM_USE_LINKER=lld \
     -DLLVM_PARALLEL_LINK_JOBS=1 \
     -DCMAKE_BUILD_TYPE=Debug \
     -DLLVM_ENABLE_ASSERTIONS=ON \
     -DLLVM_TARGETS_TO_BUILD="AMDGPU;PowerPC;AArch64;X86" \
     -DLLVM_ENABLE_DUMP=ON

3. Build Clang:

   ninja clang

4. Observe the warning during compilation of:

   clang/lib/Sema/SemaTemplateInstantiate.cpp
   

Analysis

The expression triggering the warning is:

assert(!Success || !Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction.");

Operator precedence causes && to bind tighter than ||, which may lead to ambiguous intent. Although semantically correct, adding parentheses improves clarity and suppresses warnings.

Proposed Fix

Wrap the && clause with parentheses for clarity:

assert(!Success || (!Trap.hasErrorOccurred() &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction."));

[shafik]

The fix does not look correct, it should likely be:

assert((!Success || !Trap.hasErrorOccurred()) &&
       "Substitution failures must be handled "
       "by CheckConstraintSatisfaction.");

The string literal is only for a descriptive messages on failure of the assert conditions.

[zyn0217]

I'd like to fix the issue myself because this was brought by the normalization patch