fixed some -Wsuggest-attribute=returns_nonnull GCC warnings

cmake/compileroptions.cmake

@@ -69,6 +69,7 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     add_compile_options(-Wsuggest-attribute=noreturn)
     add_compile_options(-Wno-shadow)                # whenever a local variable or type declaration shadows another one
     add_compile_options_safe(-Wuseless-cast)
+    # add_compile_options_safe(-Wsuggest-attribute=returns_nonnull) # reports the warning even if the attribute is set
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL 14 OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 14)
         # TODO: verify this regression still exists in clang-15

lib/clangimport.cpp

@@ -362,7 +362,7 @@ namespace clangimport {
         void addFullScopeNameTokens(TokenList &tokenList, const Scope *recordScope);
         Scope *createScope(TokenList &tokenList, Scope::ScopeType scopeType, AstNodePtr astNode, const Token *def);
         Scope *createScope(TokenList &tokenList, Scope::ScopeType scopeType, const std::vector<AstNodePtr> &children2, const Token *def);
-        Token *createTokensCall(TokenList &tokenList);
+        RET_NONNULL Token *createTokensCall(TokenList &tokenList);
         void createTokensFunctionDecl(TokenList &tokenList);
         void createTokensForCXXRecord(TokenList &tokenList);
         Token *createTokensVarDecl(TokenList &tokenList);

lib/cppcheck.h

@@ -116,15 +116,15 @@ class CPPCHECKLIB CppCheck : ErrorLogger {
      * @brief Returns current version number as a string.
      * @return version, e.g. "1.38"
      */
-    static const char * version();
+    RET_NONNULL static const char * version();
 
     /**
      * @brief Returns extra version info as a string.
      * This is for returning extra version info, like Git commit id, build
      * time/date etc.
      * @return extra version info, e.g. "04d42151" (Git commit id).
      */
-    static const char * extraVersion();
+    RET_NONNULL static const char * extraVersion();
 
     /**
      * @brief Call all "getErrorMessages" in all registered Check classes.

lib/ctu.h

@@ -144,7 +144,7 @@ namespace CTU {
     CPPCHECKLIB std::string getFunctionId(const Tokenizer &tokenizer, const Function *function);
 
     /** @brief Parse current TU and extract file info */
-    CPPCHECKLIB FileInfo *getFileInfo(const Tokenizer &tokenizer);
+    CPPCHECKLIB RET_NONNULL FileInfo *getFileInfo(const Tokenizer &tokenizer);
 
     CPPCHECKLIB std::list<FileInfo::UnsafeUsage> getUnsafeUsage(const Tokenizer &tokenizer, const Settings &settings, bool (*isUnsafeUsage)(const Settings &settings, const Token *argtok, MathLib::bigint *value));
 

lib/symboldatabase.h

@@ -1015,7 +1015,7 @@ class CPPCHECKLIB Function {
     void isInlineKeyword(bool state) {
         setFlag(fIsInlineKeyword, state);
     }
-    const Token *setFlags(const Token *tok1, const Scope *scope);
+    RET_NONNULL const Token *setFlags(const Token *tok1, const Scope *scope);
 };
 
 class CPPCHECKLIB Scope {
@@ -1440,7 +1440,7 @@ class CPPCHECKLIB SymbolDatabase {
     void debugSymbolDatabase() const;
 
     void addClassFunction(Scope *&scope, const Token *&tok, const Token *argStart);
-    static Function *addGlobalFunctionDecl(Scope*& scope, const Token* tok, const Token *argStart, const Token* funcStart);
+    RET_NONNULL static Function *addGlobalFunctionDecl(Scope*& scope, const Token* tok, const Token *argStart, const Token* funcStart);
     Function *addGlobalFunction(Scope*& scope, const Token*& tok, const Token *argStart, const Token* funcStart);
     void addNewFunction(Scope *&scope, const Token *&tok);
     bool isFunction(const Token *tok, const Scope* outerScope, const Token *&funcStart, const Token *&argStart, const Token*& declEnd) const;

lib/tokenize.h

@@ -172,7 +172,7 @@ class CPPCHECKLIB Tokenizer {
      * '; int *p(0);' => '; int *p = 0;'
      */
     void simplifyInitVar();
-    static Token* initVar(Token* tok);
+    RET_NONNULL static Token* initVar(Token* tok);
 
     /**
      * Simplify the location of "static" and "const" qualifiers in

lib/tokenlist.h

@@ -94,7 +94,7 @@ class CPPCHECKLIB TokenList {
      * @param one_line true=>copy all tokens to the same line as dest. false=>copy all tokens to dest while keeping the 'line breaks'
      * @return new location of last token copied
      */
-    static Token *copyTokens(Token *dest, const Token *first, const Token *last, bool one_line = true);
+    RET_NONNULL static Token *copyTokens(Token *dest, const Token *first, const Token *last, bool one_line = true);
 
     /**
      * Create tokens from code.

lib/vfvalue.h

@@ -327,10 +327,10 @@ namespace ValueFlow
 
         enum class LifetimeScope : std::uint8_t { Local, Argument, SubFunction, ThisPointer, ThisValue } lifetimeScope = LifetimeScope::Local;
 
-        static const char* toString(MoveKind moveKind);
-        static const char* toString(LifetimeKind lifetimeKind);
-        static const char* toString(LifetimeScope lifetimeScope);
-        static const char* toString(Bound bound);
+        RET_NONNULL static const char* toString(MoveKind moveKind);
+        RET_NONNULL static const char* toString(LifetimeKind lifetimeKind);
+        RET_NONNULL static const char* toString(LifetimeScope lifetimeScope);
+        RET_NONNULL static const char* toString(Bound bound);
 
         /** How known is this value */
         enum class ValueKind : std::uint8_t {

lib/xml.h

@@ -22,6 +22,7 @@
 #include "config.h"
 #include "path.h"
 
+SUPPRESS_WARNING_GCC_PUSH("-Wsuggest-attribute=returns_nonnull")
 SUPPRESS_WARNING_CLANG_PUSH("-Wzero-as-null-pointer-constant")
 SUPPRESS_WARNING_CLANG_PUSH("-Wsuggest-destructor-override")
 SUPPRESS_WARNING_CLANG_PUSH("-Winconsistent-missing-destructor-override")
@@ -31,6 +32,7 @@ SUPPRESS_WARNING_CLANG_PUSH("-Winconsistent-missing-destructor-override")
 SUPPRESS_WARNING_CLANG_POP
 SUPPRESS_WARNING_CLANG_POP
 SUPPRESS_WARNING_CLANG_POP
+SUPPRESS_WARNING_GCC_POP
 
 inline static tinyxml2::XMLError xml_LoadFile(tinyxml2::XMLDocument& doc, const char* filename)
 {