[clang-tidy] Improving narrowing conversions

Summary:
Newly flagged narrowing conversions:
 - integer to narrower signed integer (this is compiler implementation defined),
 - integer - floating point narrowing conversions,
 - floating point - integer narrowing conversions,
 - constants with narrowing conversions (even in ternary operator).

Reviewers: hokein, alexfh, aaron.ballman, JonasToth

Reviewed By: aaron.ballman, JonasToth

Subscribers: lebedev.ri, courbet, nemanjai, xazax.hun, kbarton, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D53488

llvm-svn: 347570

1 files changed, 23 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/cppcoreguidelines-narrowing-conversions-pedanticmode-option.cpp b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-narrowing-conversions-pedanticmode-option.cpp
new file mode 100644
index 00000000000..f28985d2f31
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-narrowing-conversions-pedanticmode-option.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-narrowing-conversions %t \
+// RUN: -config="{CheckOptions: [ \
+// RUN:   {key: "cppcoreguidelines-narrowing-conversions.PedanticMode", value: 1} \
+// RUN: ]}" \
+// RUN: -- -target x86_64-unknown-linux -fsigned-char
+
+namespace floats {
+
+void triggers_wrong_constant_type_warning(double d) {
+  int i = 0.0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: constant value should be of type of type 'int' instead of 'double' [cppcoreguidelines-narrowing-conversions]
+  i += 2.0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: constant value should be of type of type 'int' instead of 'double' [cppcoreguidelines-narrowing-conversions]
+  i += 2.0f;
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: constant value should be of type of type 'int' instead of 'float' [cppcoreguidelines-narrowing-conversions]
+}
+
+void triggers_narrowing_warning_when_overflowing() {
+  unsigned short us = 65537.0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: narrowing conversion from constant 'double' to 'unsigned short' [cppcoreguidelines-narrowing-conversions]
+}
+
+} // namespace floats