fix #659 - has opEquals but not toHash warning even if opEquals is disabled

src/dscanner/analysis/opequals_without_tohash.d

@@ -54,6 +54,19 @@ final class OpEqualsWithoutToHashCheck : BaseAnalyzer
 			if (!declaration || !declaration.functionDeclaration)
 				continue;
 
+			bool containsDisable(A)(const A[] attribs)
+			{
+				import std.algorithm.searching : canFind;
+				return attribs.canFind!(a => a.atAttribute !is null &&
+					a.atAttribute.identifier.text == "disable");
+			}
+
+			const isDeclationDisabled = containsDisable(declaration.attributes) ||
+				containsDisable(declaration.functionDeclaration.memberFunctionAttributes);
+
+			if (isDeclationDisabled)
+				continue;
+
 			// Check if opEquals or toHash
 			immutable string methodName = declaration.functionDeclaration.name.text;
 			if (methodName == "opEquals")
@@ -146,6 +159,13 @@ unittest
 				return 0;
 			}
 		}
+
+		// issue #659, do not warn if one miss and the other is not callable
+		struct Fox {const nothrow @safe hash_t toHash() @disable;}
+		struct Bat {@disable const nothrow @safe hash_t toHash();}
+		struct Rat {const bool opEquals(Object a, Object b) @disable;}
+		struct Cat {@disable const bool opEquals(Object a, Object b);}
+
 	}c, sac);
 
 	stderr.writeln("Unittest for OpEqualsWithoutToHashCheck passed.");