diff --git a/dexed-d/src/common.d b/dexed-d/src/common.d
index c1ebe255..749736f2 100644
--- a/dexed-d/src/common.d
+++ b/dexed-d/src/common.d
@@ -20,7 +20,7 @@ extern(C) void minimizeGcHeap()
 {
     import core.memory : GC;
     __gshared ubyte c;
-    if (c++ > 32)
+    if (c++ > 31)
     {
         GC.collect();
         GC.minimize();
diff --git a/dexed-d/src/imports.d b/dexed-d/src/imports.d
index 5c4a55e4..b96221fc 100644
--- a/dexed-d/src/imports.d
+++ b/dexed-d/src/imports.d
@@ -67,7 +67,12 @@ extern(C) string[] listFilesImports(const(char)* joinedFiles)
     LexerConfig config  = LexerConfig("", StringBehavior.source);
     ImportLister il     = construct!(ImportLister)(&result);
 
-    scope(exit) destruct(il);
+    scope(exit)
+    {
+        destruct(il);
+        destroy(sCache);
+        destroy(rba);
+    }
 
     foreach(fname; joinedFilesToFiles(joinedFiles))
     {
@@ -85,11 +90,14 @@ extern(C) string[] listFilesImports(const(char)* joinedFiles)
     return result;
 }
 
+static assert(!MustAddGcRange!ImportLister);
+
+@TellRangeAdded
 private final class ImportLister: ASTVisitor
 {
     alias visit = ASTVisitor.visit;
     size_t mixinDepth;
-    string[]* results;
+    @NoGc string[]* results;
 
     this(string[]* results)
     {
diff --git a/dexed-d/src/mainfun.d b/dexed-d/src/mainfun.d
index bac17098..5ae638dc 100644
--- a/dexed-d/src/mainfun.d
+++ b/dexed-d/src/mainfun.d
@@ -19,21 +19,26 @@ import
  */
 extern(C) bool hasMainFun(const(char)* src)
 {
-    LexerConfig config;
-    RollbackAllocator rba;
-    StringCache sCache = StringCache(StringCache.defaultBucketCount);
+    scope LexerConfig config;
+    scope RollbackAllocator rba;
+    scope StringCache sCache = StringCache(StringCache.defaultBucketCount);
 
     scope mod = src[0 .. src.strlen]
                 .getTokensForParser(config, &sCache)
                 .parseModule("", &rba, &ignoreErrors);
 
     MainFunctionDetector mfd = construct!(MainFunctionDetector);
-    scope (exit) destruct(mfd);
-
     mfd.visit(mod);
-    return mfd.hasMain;
+    const bool result = mfd.hasMain;
+    destruct(mfd);
+    destroy(sCache);
+    destroy(rba);
+    return result;
 }
 
+static assert(!MustAddGcRange!MainFunctionDetector);
+
+@TellRangeAdded
 private final class MainFunctionDetector: ASTVisitor
 {
     alias visit = ASTVisitor.visit;
@@ -58,10 +63,11 @@ private final class MainFunctionDetector: ASTVisitor
             hasMain = true;
     }
 
-    override void visit(const(Unittest)){}
-    override void visit(const(ClassDeclaration)){}
-    override void visit(const(StructDeclaration)){}
+    override void visit(const(Unittest))            {}
+    override void visit(const(ClassDeclaration))    {}
+    override void visit(const(StructDeclaration))   {}
     override void visit(const(InterfaceDeclaration)){}
-    override void visit(const(FunctionBody)){}
+    override void visit(const(UnionDeclaration))    {}
+    override void visit(const(FunctionBody))        {}
 }
 
diff --git a/src/u_ddemangle.pas b/src/u_ddemangle.pas
index f273be2a..1191c426 100644
--- a/src/u_ddemangle.pas
+++ b/src/u_ddemangle.pas
@@ -25,6 +25,7 @@ begin
     // note, assign to result has for effect to alloc a FPC string
     // (by implicit convertion) so the D memory is not used.
     result := ddemangle(s);
+    minimizeGcHeap();
   end
   else
     result := value;
diff --git a/src/u_dexed_d.pas b/src/u_dexed_d.pas
index 0a7f69ee..4e26cc30 100644
--- a/src/u_dexed_d.pas
+++ b/src/u_dexed_d.pas
@@ -48,17 +48,17 @@ const
   libdexedd_name = 'dexed-d';
 {$ENDIF}
 
-
-// Used to release memroy allocated in external D functions that are called in a thread.
-// because managing the GC only work from the main thread.
-// memory is released every 96 calls.
-procedure minimizeGcHeap(); cdecl; external libdexedd_name;
-// Select the precise GC
-procedure setRtOptions(); cdecl; external libdexedd_name;
 // Necessary to start the GC, run the static constructors, etc
 procedure rt_init(); cdecl; external libdexedd_name;
 // Cleanup
 procedure rt_term(); cdecl; external libdexedd_name;
+// Used to release memroy allocated in external D functions that are called in a thread,
+// because managing the GC only works from the main thread.
+// Memory is released every 32 calls.
+// This function must be called from the main thread.
+procedure minimizeGcHeap(); cdecl; external libdexedd_name;
+// noop
+procedure setRtOptions(); cdecl; external libdexedd_name;
 // Demangle a line possibly containing a D mangled name.
 function ddemangle(const text: PChar): PChar; cdecl; external libdexedd_name;
 // Detects wether the source code for the module `src` contains the main() function.
@@ -97,7 +97,6 @@ begin
   result := (fPtr + index)^;
 end;
 
-
 procedure getModuleImports(source, imports: TStrings);
 var
   i: TDStrings;
@@ -112,6 +111,7 @@ begin
     s := e.ptr[0 .. e.length-1];
     imports.Add(s);
   end;
+  minimizeGcHeap();
 end;
 
 procedure getModulesImports(files: string; results: TStrings);
@@ -128,6 +128,7 @@ begin
     s := e.ptr[0 .. e.length-1];
     results.Add(s);
   end;
+  minimizeGcHeap();
 end;
 
 initialization
diff --git a/src/u_synmemo.pas b/src/u_synmemo.pas
index 294a5767..13df5aad 100644
--- a/src/u_synmemo.pas
+++ b/src/u_synmemo.pas
@@ -2406,6 +2406,7 @@ begin
     false:result := mainNo;
     true: result := mainYes;
   end;
+  minimizeGcHeap();
 end;
 
 procedure TDexedMemo.autoClosePair(value: TAutoClosedPair);