[clang] [clang][analyzer] Support `fgetc` in StreamChecker (PR #72627)

[Balázs Kéri via cfe-commits]

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@@ -303,3 +346,29 @@ void error_indeterminate_feof2(void) {
   }
   fclose(F);
 }
+
+void error_indeterminate_feof3(void) {
+  FILE *F = fopen("file", "r+");
+  if (!F)
+    return;
+  if (fgetc(F) == EOF) {
+    if (feof(F)) {
+      // error is feof, should be non-indeterminate
+      fputc('A', F); // no warning
+    }
+  }
+  fclose(F);
+}
+
+void error_indeterminate_feof4(void) {
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balazske wrote:

This test seems to be not necessary (previous tests cover these conditions), otherwise a more meaningful name should be chosen for it.

https://github.com/llvm/llvm-project/pull/72627