[clang-tidy] Enhance clang-tidy readability-simplify-boolean-expr check...

Enhance clang-tidy readability-simplify-boolean-expr check to handle chained
conditional assignment and chained conditional return.

Based on feedback from applying this tool to the clang/LLVM codebase, this
changeset improves the readability-simplify-boolean-expr check so that
conditional assignment or return statements at the end of a chain of if/else if
statements are left unchanged unless a configuration option is supplied.

http://reviews.llvm.org/D8996

Patch by Richard Thomson!

llvm-svn: 237541

1 files changed, 33 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/readability-simplify-bool-expr-chained-conditional-return.cpp b/clang-tools-extra/test/clang-tidy/readability-simplify-bool-expr-chained-conditional-return.cpp
new file mode 100644
index 00000000000..d50c13ac28c
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-simplify-bool-expr-chained-conditional-return.cpp
@@ -0,0 +1,33 @@
+// RUN: $(dirname %s)/check_clang_tidy.sh %s readability-simplify-boolean-expr %t -config="{CheckOptions: [{key: "readability-simplify-boolean-expr.ChainedConditionalReturn", value: 1}]}" --
+// REQUIRES: shell
+
+bool chained_conditional_compound_return(int i) {
+  if (i < 0) {
+    return true;
+  } else if (i < 10) {
+    return false;
+  } else if (i > 20) {
+    return true;
+  } else {
+    return false;
+  }
+  // CHECK-MESSAGES: :[[@LINE-4]]:12: warning: redundant boolean literal in conditional return statement [readability-simplify-boolean-expr]
+  // CHECK-FIXES:      {{^}}  } else if (i < 10) {{{$}}
+  // CHECK-FIXES-NEXT: {{^}}    return false;{{$}}
+  // CHECK-FIXES-NEXT: {{^}}  } else return i > 20;{{$}}
+}
+
+bool chained_conditional_return(int i) {
+  if (i < 0)
+    return true;
+  else if (i < 10)
+    return false;
+  else if (i > 20)
+    return true;
+  else
+    return false;
+  // CHECK-MESSAGES: :[[@LINE-3]]:12: warning: {{.*}} in conditional return statement
+  // CHECK-FIXES:      {{^}}  else if (i < 10)
+  // CHECK-FIXES-NEXT: {{^}}    return false;
+  // CHECK-FIXES-NEXT: {{^}}  else return i > 20;
+}