[clang-tidy] Disable match on `if constexpr` statements in template instantiation for `readability-misleading-indentation` check.

[Abpostelnicu]

Summary

Fixes fixes readability-misleading-identation for if constexpr. This is very similar to D71980. The bug tracking this issue is 44490.

[Abpostelnicu]

Updated the test case to better reflect the changes.

[njames93]

I could never seem to get the tests to handle differently in templated and non templated code. Maybe i was just being stupid. Think the root cause is that the check detects if the if column appears on a different column to either the else or the closing brace if its on the same line as the else.

[Abpostelnicu]

Updated test with match without compound statement.

[JonasToth]

clang-tools-extra/test/clang-tidy/checkers/readability-misleading-indentation.cpp

172

please add an case that does not get instantiated, with both bad and good indentation.

[Abpostelnicu]

Added more tesst for templa functions that are not instantiated.

[JonasToth]

LGTM! Thank you for fixing this issue. Can you please update the bug report as well?

[thakis]

This broke tests on Windows: http://45.33.8.238/win/5297/step_8.txt (probably due to windows using -fdelayed-template-parsing by default).

[Abpostelnicu]

I think the best approach here is to remove the tests that don’t have template instantiation.

[thakis]

In D72333#1810142, @Abpostelnicu wrote:

I think the best approach here is to remove the tests that don’t have template instantiation.

In any case, if it takes a while to come to some decision, please revert in the meantime so that trunk doesn't stay red for a long time.

[Abpostelnicu]

Will push shortly an update.

[thakis]

Any luck? The bot's been broken for close to 4h now.

[JonasToth]

Adding a -fno-delayed-template-parsing to the RUN-line should suffice.

clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.cpp

if (SM.getExpansionColumnNumber(InnerLoc) ==
       diag(OuterLoc, "did you mean this line to be inside this '%0'",
            DiagnosticIDs::Note)
           << StmtNames[StmtKind];
     }
   }
 }
 
 void MisleadingIndentationCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(ifStmt(hasElse(stmt())).bind("if"), this);
+  Finder->addMatcher(
+      ifStmt(allOf(hasElse(stmt()),
+                   unless(allOf(isConstexpr(), isInTemplateInstantiation()))))
+          .bind("if"),
+      this);
   Finder->addMatcher(
       compoundStmt(has(stmt(anyOf(ifStmt(), forStmt(), whileStmt()))))
           .bind("compound"),
       this);
 }
 
 void MisleadingIndentationCheck::check(const MatchFinder::MatchResult &Result) {
   if (const auto *If = Result.Nodes.getNodeAs<IfStmt>("if"))

clang-tools-extra/test/clang-tidy/checkers/readability-misleading-indentation.cpp

 // RUN: %check_clang_tidy %s readability-misleading-indentation %t
 
 void foo1();
 void foo2();
+void foo3();
 
 #define BLOCK \
   if (cond1)  \
     foo1();   \
     foo2();
 
 void f()
 {

 void g(bool x) {
   if (x)
     #pragma unroll
     for (int k = 0; k < 1; ++k) {}
 
   #pragma unroll
   for (int k = 0; k < 1; ++k) {}
 }
+
+template<bool b>
+void mustPass() {
+  if constexpr (b) {
+    foo1();
+  } else {
+    foo2();
+  }
+}
+
+void mustPassNonTemplate() {
+  constexpr unsigned Value = 1;
+  if constexpr (Value == 0) {
+    foo1();
+  } else if constexpr (Value == 1) {
+    foo2();
+  } else {
+    foo3();
+  }
+}
+
+template<bool b>
+void mustFail() {
+  if constexpr (b) {
+    foo1();
+  }
+    else {
+      foo2();
+      // CHECK-MESSAGES: :[[@LINE-2]]:5: warning: different indentation for 'if' and corresponding 'else' [readability-misleading-indentation]
+  }
+}
+
+void mustFailNonTemplate() {
+  constexpr unsigned Value = 1;
+  if constexpr (Value == 0) {
+    foo1();
+  }
+    else {
+  foo2();
+  // CHECK-MESSAGES: :[[@LINE-2]]:5: warning: different indentation for 'if' and corresponding 'else' [readability-misleading-indentation]
+  }
+
+  if constexpr (Value == 0)
+    foo1();
+    else
+  foo2();
+  // CHECK-MESSAGES: :[[@LINE-2]]:5: warning: different indentation for 'if' and corresponding 'else' [readability-misleading-indentation]
+}
+
+template<bool b>
+void mustFailNoInsta() {
+  if constexpr (b) {
+    foo1();
+  }
+    else {
+      foo2();
+      // CHECK-MESSAGES: :[[@LINE-2]]:5: warning: different indentation for 'if' and corresponding 'else' [readability-misleading-indentation]
+  }
+}
+
+template<bool b>
+void mustPassNoInsta() {
+  if constexpr (b) {
+    foo1();
+  }
+  else {
+    foo2();
+  }
+}
+
+void call() {
+  mustPass<true>();
+  mustPass<false>();
+  mustFail<true>();
+  mustFail<false>();
+}