Warn about missing parentheses for conditional operator.

Warn in cases such as "x + someCondition ? 42 : 0;",
where the condition expression looks arithmetic, and has
a right-hand side that looks boolean.

This (partly) addresses http://llvm.org/bugs/show_bug.cgi?id=9969

llvm-svn: 132565

2 files changed, 41 insertions, 1 deletions

diff --git a/clang/test/Sema/parentheses.c b/clang/test/Sema/parentheses.c
index a25ded66a66..fa3c3c26b04 100644
--- a/clang/test/Sema/parentheses.c
+++ b/clang/test/Sema/parentheses.c
@@ -39,6 +39,28 @@ void bitwise_rel(unsigned i) {
   (void)(0 || i && i); // no warning.
 }
 
+_Bool someConditionFunc();
+
+void conditional_op(int x, int y, _Bool b) {
+  (void)(x + someConditionFunc() ? 1 : 2); // expected-warning {{?: has lower precedence than +}} \
+                                           // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                                           // expected-note {{place parentheses around the + expression to silence this warning}}
+
+  (void)(x - b ? 1 : 2); // expected-warning {{?: has lower precedence than -}} \
+                         // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                         // expected-note {{place parentheses around the - expression to silence this warning}}
+
+  (void)(x * (x == y) ? 1 : 2); // expected-warning {{?: has lower precedence than *}} \
+                                // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                                // expected-note {{place parentheses around the * expression to silence this warning}}
+
+  (void)(x / !x ? 1 : 2); // expected-warning {{?: has lower precedence than /}} \
+                          // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                          // expected-note {{place parentheses around the / expression to silence this warning}}
+
+
+  (void)(x % 2 ? 1 : 2); // no warning
+}
+
 // RUN: %clang_cc1 -fsyntax-only -Wparentheses -Werror -fdiagnostics-show-option %s 2>&1 | FileCheck %s
 // CHECK: error: using the result of an assignment as a condition without parentheses [-Werror,-Wparentheses]
-
diff --git a/clang/test/Sema/parentheses.cpp b/clang/test/Sema/parentheses.cpp
new file mode 100644
index 00000000000..ad1f399c649
--- /dev/null
+++ b/clang/test/Sema/parentheses.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify %s
+// RUN: %clang_cc1 -Wparentheses -fixit %s -o - | %clang_cc1 -Wparentheses -Werror -
+
+bool someConditionFunc();
+
+void conditional_op(int x, int y, bool b) {
+  (void)(x + someConditionFunc() ? 1 : 2); // expected-warning {{?: has lower precedence than +}} \
+                                           // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                                           // expected-note {{place parentheses around the + expression to silence this warning}}
+
+  (void)(x - b ? 1 : 2); // expected-warning {{?: has lower precedence than -}} \
+                         // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                         // expected-note {{place parentheses around the - expression to silence this warning}}
+
+  (void)(x * (x == y) ? 1 : 2); // expected-warning {{?: has lower precedence than *}} \
+                                // expected-note {{place parentheses around the ?: expression to evaluate it first}} \
+                                // expected-note {{place parentheses around the * expression to silence this warning}}
+}