| Issue |
164104
|
| Summary |
SemaTemplateInstantiate.cpp: warning: suggest parentheses around ‘&&’ within ‘||’
|
| Labels |
new issue
|
| Assignees |
aabhinavg1
|
| Reporter |
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:
```bash
git clone https://github.com/llvm/llvm-project.git
cd llvm-project
mkdir build && cd build
```
2. Configure the build using CMake:
```bash
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:
```bash
ninja clang
```
4. Observe the warning during compilation of:
```
clang/lib/Sema/SemaTemplateInstantiate.cpp
```
## Analysis
The _expression_ triggering the warning is:
```cpp
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:
```cpp
assert(!Success || (!Trap.hasErrorOccurred() &&
"Substitution failures must be handled "
"by CheckConstraintSatisfaction."));
```
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