Avoid casts that don't change the pointer type

.ci/linters/c/cocci_linter.R

@@ -0,0 +1,20 @@
+cocci_linter = if (!nzchar(Sys.which("spatch"))) function(...) {} else function(c_obj) {
+  bad <- FALSE
+  for (spfile in list.files(".ci/linters/cocci", full.names = TRUE)) {
+    # Coccinelle parser gets confused sometimes, so ignore stderr and the exit code
+    out = suppressWarnings(system2(
+      "spatch",
+      shQuote(c(
+        "--sp-file", spfile, c_obj$path, "--recursive-includes",
+        "-I", R.home("include"), "-I", "src"
+      )),
+      stdout = TRUE, stderr = FALSE
+    ))
+    if (length(out) > 0) {
+      cat(sprintf("In file '%s', Coccinelle patch '%s' recommends the following changes:\n", c_obj$path, spfile))
+      writeLines(out)
+      bad <- TRUE
+    }
+  }
+  if (bad) stop("Please apply the changes above or fix the linter")
+}

.ci/linters/cocci/redundant_cast_to_same_pointer_type.cocci

@@ -0,0 +1,6 @@
+@@
+type T;
+T* E;
+@@
+- (T*)
+  E

.github/workflows/code-quality.yaml

@@ -35,6 +35,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: r-lib/actions/setup-r@v2
+      - name: Install Coccinelle
+        # relying on the action above us to have updated the package cache
+        run: /usr/bin/sudo apt-get -y install coccinelle
       - name: Lint
         run: |
           linter_env = new.env()

src/assign.c

@@ -1207,7 +1207,7 @@ void writeNA(SEXP v, const int from, const int n, const bool listNA)
     memset(RAW(v)+from, 0, n*sizeof(Rbyte));
     break;
   case LGLSXP: {
-    int *vd = (int *)LOGICAL(v);
+    int *vd = LOGICAL(v);
     for (int i=from; i<=to; ++i) vd[i] = NA_LOGICAL;
   } break;
   case INTSXP: {

src/coalesce.c

@@ -100,7 +100,7 @@ SEXP coalesce(SEXP x, SEXP inplaceArg) {
         if (val!=NA_INTEGER64) xP[i]=val; else if (final) xP[i]=finalVal;
       }
     } else {
-      double *xP = (double *)REAL(first), finalVal=NA_REAL;
+      double *xP = REAL(first), finalVal=NA_REAL;
       int k=0;
       for (int j=0; j<nval; ++j) {
         SEXP item = VECTOR_ELT(x, j+off);

src/fread.c

@@ -441,7 +441,7 @@ static const char* filesize_to_str(size_t fsize)
 double copyFile(size_t fileSize)  // only called in very very rare cases
 {
   double tt = wallclock();
-  mmp_copy = (char *)malloc((size_t)fileSize + 1 /* extra \0 */);
+  mmp_copy = (char *)malloc(fileSize + 1 /* extra \0 */);
   if (!mmp_copy)
     return -1.0; // # nocov
   memcpy(mmp_copy, mmp, fileSize);

src/freadR.c

@@ -624,7 +624,7 @@ void pushBuffer(ThreadLocalFreadParsingContext *ctx)
     resj++;
     if (type[j]!=CT_STRING && type[j]>0) {
       if (thisSize == 8) {
-        double *dest = (double *)REAL(VECTOR_ELT(DT, resj)) + DTi;
+        double *dest = REAL(VECTOR_ELT(DT, resj)) + DTi;
         const char *src8 = (char*)buff8 + off8;
         for (int i=0; i<nRows; ++i) {
           *dest = *(double *)src8;
@@ -633,7 +633,7 @@ void pushBuffer(ThreadLocalFreadParsingContext *ctx)
         }
       } else
       if (thisSize == 4) {
-        int *dest = (int *)INTEGER(VECTOR_ELT(DT, resj)) + DTi;
+        int *dest = INTEGER(VECTOR_ELT(DT, resj)) + DTi;
         const char *src4 = (char*)buff4 + off4;
         // debug line for #3369 ... if (DTi>2638000) printf("freadR.c:460: thisSize==4, resj=%d, %"PRIu64", %d, %d, j=%d, done=%d\n", resj, (uint64_t)DTi, off4, rowSize4, j, done);
         for (int i=0; i<nRows; ++i) {

src/ijoin.c

@@ -10,8 +10,8 @@ SEXP lookup(SEXP ux, SEXP xlen, SEXP indices, SEXP gaps, SEXP overlaps, SEXP mul
 
   SEXP vv, tt, lookup, type_lookup;
   R_len_t *idx,*count,*type_count,xrows=INTEGER(xlen)[0],uxrows=LENGTH(VECTOR_ELT(ux, 0)),uxcols=LENGTH(ux);
-  int *from = (int *)INTEGER(VECTOR_ELT(indices, 0));
-  int *to   = (int *)INTEGER(VECTOR_ELT(indices, 1));
+  int *from = INTEGER(VECTOR_ELT(indices, 0));
+  int *to   = INTEGER(VECTOR_ELT(indices, 1));
   clock_t pass1, pass2, pass3, start;
   enum {ALL, FIRST, LAST} mult = ALL;
   enum {ANY, WITHIN, START, END, EQUAL} type = ANY;
@@ -31,8 +31,8 @@ SEXP lookup(SEXP ux, SEXP xlen, SEXP indices, SEXP gaps, SEXP overlaps, SEXP mul
   // For reference: uxcols-1 = type_count, uxcols-2 = count, uxcols-3 = type_lookup, uxcols-4 = lookup
   // first pass: calculate lengths first
   start = clock();
-  count = (int *)INTEGER(VECTOR_ELT(ux, uxcols-2));
-  type_count = (int *)INTEGER(VECTOR_ELT(ux, uxcols-1));
+  count = INTEGER(VECTOR_ELT(ux, uxcols-2));
+  type_count = INTEGER(VECTOR_ELT(ux, uxcols-1));
   switch (mult) {
   case FIRST:
     switch(type) {
@@ -225,10 +225,10 @@ SEXP overlaps(SEXP ux, SEXP imatches, SEXP multArg, SEXP typeArg, SEXP nomatchAr
 
   R_len_t uxcols=LENGTH(ux),rows=length(VECTOR_ELT(imatches,0));
   int nomatch = INTEGER(nomatchArg)[0], totlen=0, thislen;
-  int *from   = (int *)INTEGER(VECTOR_ELT(imatches, 0));
-  int *to     = (int *)INTEGER(VECTOR_ELT(imatches, 1));
-  int *count   = (int *)INTEGER(VECTOR_ELT(ux, uxcols-2));
-  int *type_count   = (int *)INTEGER(VECTOR_ELT(ux, uxcols-1));
+  int *from   = INTEGER(VECTOR_ELT(imatches, 0));
+  int *to     = INTEGER(VECTOR_ELT(imatches, 1));
+  int *count   = INTEGER(VECTOR_ELT(ux, uxcols-2));
+  int *type_count   = INTEGER(VECTOR_ELT(ux, uxcols-1));
   SEXP lookup = VECTOR_ELT(ux, uxcols-4);
   SEXP type_lookup = VECTOR_ELT(ux, uxcols-3);
   SEXP ans, f1__, f2__, tmp1, tmp2;

src/negate.c

@@ -5,7 +5,7 @@ void negateByRef(SEXP x) {
     error("not logical or integer vector");  // # nocov
   }
   const int n = length(x);
-  int *ansd = (int *)LOGICAL(x);
+  int *ansd = LOGICAL(x);
   for(int i=0; i<n; ++i) {
     ansd[i] ^= (ansd[i] != NA_LOGICAL);  // invert true/false but leave NA alone
   }

src/reorder.c

@@ -63,7 +63,7 @@ SEXP reorder(SEXP x, SEXP order)
     // This check is once up front, and then idx is applied to all the columns which is where the most time is spent.
   }
 
-  char *TMP = (char *)R_alloc(nmid, maxSize);
+  char *TMP = R_alloc(nmid, maxSize);
 
   for (int i=0; i<ncol; ++i) {
     const SEXP v = isNewList(x) ? VECTOR_ELT(x,i) : x;