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[docs][methods][10/n] add alias limiation
This shows that in the presence of aliases, the analyzer avoid duplicate reports but also fails to properly track uses through aliases, resulting in false positives.
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15 files changed

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-16
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15 files changed

+196
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‎check/classic/classic.exp‎

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@@ -159,6 +159,8 @@ Nothing else to report in this section
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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‎check/classic/classic.ref‎

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@@ -164,6 +164,8 @@ Nothing else to report in this section
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Should not be detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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@@ -636,7 +638,7 @@ Nothing else to report in this section
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--------------------------------------------------------------------------------
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Total: 544
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Success: 539
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Failed: 5
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Ratio: 99.0808823529%
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Total: 546
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Success: 540
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Failed: 6
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Ratio: 98.9010989011%

‎check/internal/internal.exp‎

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@@ -114,6 +114,8 @@ Nothing else to report in this section
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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‎check/internal/internal.ref‎

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@@ -119,6 +119,8 @@ Nothing else to report in this section
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Should not be detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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@@ -591,7 +593,7 @@ Nothing else to report in this section
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--------------------------------------------------------------------------------
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Success: 497
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Ratio: 99.0039840637%
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Total: 504
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Success: 498
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Ratio: 98.8095238095%

‎check/threshold-1/threshold-1.exp‎

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@@ -150,6 +150,8 @@
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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:4: push_n_times
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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:10: clear_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:8: alias
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_lib.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_no_intf.mli:1: mark_used
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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@@ -441,6 +445,9 @@ Nothing else to report in this section
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used_by_child
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#externally_used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#internally_used
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#externally_used

‎check/threshold-1/threshold-1.ref‎

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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:4: push_n_times
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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:10: clear_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:8: alias
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_lib.mli:1: mark_used
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Should not be detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used_by_child
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Not detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#externally_used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#internally_used
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--------------------------------------------------------------------------------
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Total: 854
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Total: 859
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Success: 852
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Ratio: 99.1850989523%

‎check/threshold-3-0.5/threshold-3-0.5.exp‎

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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:4: push_n_times
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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:10: clear_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:8: alias
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_lib.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_no_intf.mli:1: mark_used
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./examples/docs/methods/code_constructs/object_type/object_type_lib.mli:17: int_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original
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./examples/using_dune/preprocessed_lib/preprocessed.mli:2: used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:31: exported_f
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#externally_used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#internally_used
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#externally_used

‎check/threshold-3-0.5/threshold-3-0.5.ref‎

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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:4: push_n_times
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./examples/docs/methods/code_constructs/object_type/object_type_bin.ml:10: clear_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:8: alias
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed.mli:1: mark_used
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./examples/using_dune/bin/use_preprocessed_lib/use_preprocessed_lib.mli:1: mark_used
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./examples/docs/methods/code_constructs/object_type/object_type_lib.mli:17: int_stack
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original
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./examples/using_dune/preprocessed_lib/preprocessed.mli:2: used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:31: exported_f
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./examples/using_dune/preprocessed_lib/preprocessed.mli:38: internally_used_f
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Should not be detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#unused
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#unused
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./examples/docs/methods/code_constructs/inheritance/inheritance_lib.mli:2: parent#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used
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./examples/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias: Not detected
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#externally_used
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./examples/using_dune/preprocessed_lib/preprocessed.mli:6: immediate#internally_used
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./examples/using_dune/preprocessed_lib/preprocessed_no_intf.ml:12: immediate#externally_used
@@ -1409,7 +1417,7 @@ Nothing else to report in this section
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--------------------------------------------------------------------------------
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Total: 1180
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Success: 1175
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Failed: 5
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Ratio: 99.5762711864%
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Total: 1186
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Success: 1179
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Ratio: 99.4097807757%

‎docs/methods/METHODS.md‎

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As explained in the [Object type](./code_constructs/OBJECT_TYPE.md) example, the
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analyzer is currently restricted to not reporting methods declared in object
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types.
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## Alias
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In the presence of multiple bindings to the same object, the analyzer corrctly
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avoids tracking their methods individually. However, it fails at unifying them
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and only keeps track of the methods used through the original binding, where the
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methods are defined. This leads to **false positives**.
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### Example
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The reference files for this example are in the
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[alias](../../examples/docs/methods/limitations/alias) directory.
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The reference takes place in `/tmp/docs/methods/limitations`, which
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is a copy of the [limiations](../../../examples/docs/methods/limitations)
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directory. Reported locations may differ depending on the location of the source
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files.
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The compilation command is :
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```
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make -C alias build
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```
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The analysis command is :
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```
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make -C alias analyze
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```
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The compile + analyze command is :
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```
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make -C alias
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```
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Code:
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Code:
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```OCaml
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(* alias_lib.mli *)
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val original : <
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used : unit;
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used_by_alias : unit;
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unused : unit
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>
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val alias : <
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used : unit;
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used_by_alias : unit;
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unused : unit
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>
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```
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```OCaml
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(* alias_lib.ml *)
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let original = object
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method used = ()
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method used_by_alias = ()
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method unused = ()
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end
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let alias = original
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```
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```OCaml
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(* alias_bin.ml *)
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open Alias_lib
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let () =
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original#used;
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alias#used_by_alias
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```
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Compile and analyze:
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```
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$ make -C alias
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make: Entering directory '/tmp/docs/methods/limitations/alias'
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ocamlopt -bin-annot alias_lib.mli alias_lib.ml alias_bin.ml
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dead_code_analyzer --nothing -M all .
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Scanning files...
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[DONE]
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.> UNUSED METHODS:
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=================
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/tmp/docs/methods/limitations/alias/alias_lib.mli:2: original#unused
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/tmp/docs/methods/limitations/alias/alias_lib.mli:2: original#used_by_alias
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Nothing else to report in this section
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--------------------------------------------------------------------------------
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make: Leaving directory '/tmp/docs/methods/limitations/alias'
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```
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The analyzer reports `original#used_by_alias` although it is used by
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`alias#used_by_alias`.

‎examples/docs/methods/Makefile‎

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build:
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make -C code_constructs
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make -C limitations
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clean:
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rm -f *~ *.cm* *.o *.obj
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make -C code_constructs clean
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make -C limitations clean
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